Strategic Implementation of a New Robotic Mitral Repair Program: Early Experience and Outcomes.

BACKGROUND: Despite numerous reported benefits of robotic mitral repair, the absolute number of procedures performed remain low in part to uncertainties about the necessary steps to launch a program. In this report, we describe our early outcomes and strategy with launching a successful new robotic mitral repair program. METHODS: Our multimodal strategic plan emphasized team education, hands-on technical preparation, stepwise advancement, and careful patient selection. Consultant service analytics and team debriefings allowed for iterative improvements. RESULTS: Between March 2022 through February 2024, 50 patients underwent robotic mitral repair at our institution. Average age at time of operation was 62 with an STS risk score of 0.58. Successful repairs were performed in 98% of patients. There was one conversion to sternotomy. There were no deaths and minimal perioperative morbidity. On both predischarge and follow-up echocardiography, no patients had greater than mild mitral regurgitation. CONCLUSIONS: Our work provides a model for establishing a successful robotic mitral program. An upfront emphasis on team education, careful preparation, proper patient selection, and feedback-driven improvements can accelerate the attainment of standards set by high-volume centers.

Re-repair for mitral insufficiency.

BACKGROUND: Mitral valve repair provides superior outcomes to replacement for primary MR. Whether this is true following previous repair is unknown. We present the results of a strategy of re-repair for failed mitral valve repair. We examine patients who were brought to the operating room for an intended mitral valve re-repair. METHODS: We reviewed the last one decade of our institutional mitral valve databases at The University of Pennsylvania and Plano Heart Hospital and identified patients undergoing repeat mitral valve repair, in whom the index operation was mitral valve repair. We analyzed their operative details, clinical and echocardiographic outcomes. RESULTS: Between 2008 and 2021, 71 patients (aged 61.5 ±10.7 years, 20% female) underwent mitral valve reoperation at an mean of 6.24 ±7.62 years following index mitral repair. 20% of patients presented with NYHA class III/IV symptoms. At index operation, 34 (47.9%) had repair through a right mini-thoracotomy. 15 patients (21.1%) required the reoperation within one year. There were 0 early and 8 late deaths. One patient who underwent mitral replacement instead of repair, required reoperation for paravalvular leak during the follow-up period. Three patients required mitral valve replacement at an average of 2.28 ±2.03 years following initial mitral valve re-repair. CONCLUSIONS: Mitral re-repair can be performed with acceptable results at a valve reference center. Durability and functional advantages of this approach remain to be proven.

Anaerobic Lactate Production Is Associated With Decreased Microcirculatory Blood Flow and Decreased Mitochondrial Respiration Following Cardiovascular Surgery With Cardiopulmonary Bypass.

OBJECTIVES: Quantify the relationship between perioperative anaerobic lactate production, microcirculatory blood flow, and mitochondrial respiration in patients after cardiovascular surgery with cardiopulmonary bypass. DESIGN: Serial measurements of lactate-pyruvate ratio (LPR), microcirculatory blood flow, plasma tricarboxylic acid cycle cycle intermediates, and mitochondrial respiration were compared between patients with a normal peak lactate (≤ 2 mmol/L) and a high peak lactate (≥ 4 mmol/L) in the first 6 hours after surgery. Regression analysis was performed to quantify the relationship between clinically relevant hemodynamic variables, lactate, LPR, and microcirculatory blood flow. SETTING: This was a single-center, prospective observational study conducted in an academic cardiovascular ICU. PATIENTS: One hundred thirty-two patients undergoing elective cardiovascular surgery with cardiopulmonary bypass. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients with a high postoperative lactate were found to have a higher LPR compared with patients with a normal postoperative lactate (14.4 ± 2.5 vs. 11.7 ± 3.4; p = 0.005). Linear regression analysis found a significant, negative relationship between LPR and microcirculatory flow index ( r = -0.225; ß = -0.037; p = 0.001 and proportion of perfused vessels: r = -0.17; ß = -0.468; p = 0.009). There was not a significant relationship between absolute plasma lactate and microcirculation variables. Last, mitochondrial complex I and complex II oxidative phosphorylation were reduced in patients with high postoperative lactate levels compared with patients with normal lactate (22.6 ± 6.2 vs. 14.5 ± 7.4 pmol O 2 /s/10 6 cells; p = 0.002). CONCLUSIONS: Increased anaerobic lactate production, estimated by LPR, has a negative relationship with microcirculatory blood flow after cardiovascular surgery. This relationship does not persist when measuring lactate alone. In addition, decreased mitochondrial respiration is associated with increased lactate after cardiovascular surgery. These findings suggest that high lactate levels after cardiovascular surgery, even in the setting of normal hemodynamics, are not simply a type B phenomenon as previously suggested.

Circulating T cell specific extracellular vesicle profiles in cardiac allograft acute cellular rejection.

There is a critical need for biomarkers of acute cellular rejection (ACR) in organ transplantation. We hypothesized that ACR leads to changes in donor-reactive T cell small extracellular vesicle (sEV) profiles in transplant recipient circulation that match the kinetics of alloreactive T cell activation. In rodent heart transplantation, circulating T cell sEV quantities (P < .0001) and their protein and mRNA cargoes showed time-specific expression of alloreactive and regulatory markers heralding early ACR in allogeneic transplant recipients but not in syngeneic transplant recipients. Next generation sequencing of their microRNA cargoes identified novel candidate biomarkers of ACR, which were validated by stem loop quantitative reverse transcription polymerase chain reaction (n = 10). Circulating T cell sEVs enriched from allogeneic transplant recipients mediated targeted cytotoxicity of donor cardiomyocytes by apoptosis assay (P < .0001). Translation of the concept and EV methodologies to clinical heart transplantation demonstrated similar upregulation of circulating T cell sEV profiles at time points of grade 2 ACR (n = 3 patients). Furthermore, T cell receptor sequencing of T cell sEV mRNA cargo demonstrated expression of T cell clones with intact complementarity determining region 3 signals. These data support the diagnostic potential of T cell sEVs as noninvasive biomarker of ACR and suggest their potential functional roles.

Low postoperative perfused vessel density is associated with increased soluble endothelial cell adhesion molecules during circulatory shock after cardiac surgery.

INTRODUCTION: Microcirculatory dysfunction after cardiovascular surgery is associated with significant morbidity and worse clinical outcomes. Abnormal capillary blood flow can occur from multiple causes, including cytokine-mediated vascular endothelial injury, microthrombosis, and an inadequate balance between vasoconstriction and vasodilation. In response to proinflammatory cytokines, endothelial cells produce cellular adhesion molecules (CAMs) which regulate leukocyte adhesion, vascular permeability, and thus can mediate tissue injury. The relationship between changes in microcirculatory flow during circulatory shock and circulating adhesion molecules is unclear. The objective of this study was to compare changes in plasma soluble endothelial cell adhesion molecules (VCAM-1, ICAM-1, and E-Selectin) in patients with functional derangements in microcirculatory blood flow after cardiovascular surgery. METHODS: Adult patients undergoing elective cardiac surgery requiring cardiopulmonary bypass who exhibited postoperative shock were enrolled in the study. Sublingual microcirculation imaging was performed prior to surgery and within 2 h of ICU admission. Blood samples were taken at the time of microcirculation imaging for biomarker analysis. Plasma soluble VCAM-1, ICAM-1, and E-selectin in addition to plasma cytokines (IL-6, IL-8, and IL-10) were measured by commercially available enzyme-linked immunoassay. RESULTS: Of 83 patients with postoperative shock who were evaluated, 40 patients with clinical shock had a postoperative perfused vessel density (PVD) >1 SD above (High PVD group = 28.5 ± 2.3 mm/mm2, n = 20) or below (Low PVD = 15.5 ± 2.0 mm/mm2, n = 20) the mean postoperative PVD and were included in the final analysis. Patient groups were well matched for comorbidities, surgical, and postoperative details. Overall, there was an increase in postoperative plasma VCAM-1 and E-Selectin compared to preoperative levels, but there was no difference between circulating ICAM-1. When grouped by postoperative microcirculation, patients with poor microcirculation were found to have increased circulating VCAM-1 (2413 ± 1144 vs. 844 ± 786 ng/mL; p < 0.0001) and E-Selectin (242 ± 119 vs. 87 ± 86 ng/mL; p < 0.0001) compared to patients with increased microcirculatory blood flow. Microcirculatory flow was not associated with a difference in plasma soluble ICAM-1 (394 ± 190 vs. 441 ± 256; p = 0.52). CONCLUSIONS: Poor postoperative microcirculatory blood flow in patients with circulatory shock after cardiac surgery is associated with increased plasma soluble VCAM-1 and E-Selectin, indicating increased endothelial injury and activation compared to patients with a high postoperative microcirculatory blood flow. Circulating endothelial cell adhesion molecules may be a useful plasma biomarker to identify abnormal microcirculatory blood flow in patients with shock.

Robotic and endoscopic mitral valve repair for degenerative disease.

Background: Minimally invasive mitral valve repair has been proven to be a safe alternative to open sternotomy and may be accomplished through classic endoscopic and robotic endoscopic approaches. Outcomes across different minimally invasive techniques have been insufficiently described. We compare early and late clinical outcomes across matched patients undergoing robotic endoscopic and classic endoscopic repair. Methods: From 2011 to 2020, 786 patients underwent minimally invasive mitral surgery, from which we were able to generate 124 matched patients (62 patients in each cohort). Clinical results were then compared between the two matched populations. Survival analysis was used to compare freedom from mortality to 10 years among matched classic endoscopic and robotic endoscopic mitral valve repair cohorts and to calculate freedom from moderate or severe mitral insufficiency at latest follow-up. Histograms of cardiopulmonary bypass (CPB) and aortic cross-clamp times were constructed, and mean bypass and cross-clamp times were compared between classic endoscopic and robotic endoscopic cohorts. Results: There was no difference in early or late mortality at 10 years in either cohort. Freedom from moderate or severe mitral regurgitation or mitral valve replacement at last echocardiogram was 86.4% vs. 73.5% at 10 years, P=0.97. Patients undergoing robotic endoscopic mitral repair had a significantly longer CPB run when compared to the classic endoscopic cohort, with 148 min of CPB in the robotic endoscopic cohort compared to 133 min in the classic endoscopic group, P=0.03. Overall post-operative length of stay was not statistically significant between the robotic endoscopic and classic endoscopic groups, 6.3±0.5 and 6.0±0.3 days, respectively. No patients in either cohort developed renal failure or wound infection. The classic endoscopic group had a slightly higher risk of prolonged ventilation when compared to the robotic endoscopic group, with three classic endoscopic patients remaining intubated >8 hours post-operatively, compared to a single patient in the robotic endoscopic group. There were no unplanned reoperations in either group. Rates of postoperative stroke were comparable between groups (three in the classic endoscopic cohort, and two in the robotic endoscopic cohort). Conclusions: Index mitral valve surgery via a classic endoscopic approach yields similar clinical outcomes when compared to robotic endoscopic surgery. We demonstrate that both classic endoscopic and robotic endoscopic approaches allow repair of degenerative mitral valves with excellent short- and medium-term outcomes in a tertiary referral center.

Intimal hyperplasia, saphenous vein graft disease, and clinical outcomes: Insights from the CTSN VEST randomized trial.

BACKGROUND: Diffuse intimal hyperplasia and graft irregularity adversely affect the long-term patency of saphenous vein grafts (SVGs) and clinical outcomes of patients undergoing coronary artery bypass grafting (CABG). The VEST trial evaluated the efficacy of external graft support in limiting the development of intimal hyperplasia (IH) at 1 year postsurgery. In the present secondary analysis, we explored the associations between graft disease and IH and clinical events. We also examined risk factors for early graft occlusion. METHODS: VEST is a within-patient randomized, multicenter trial that enrolled 224 patients with multivessel coronary disease undergoing CABG surgery, of whom 203 were evaluated by 1 year postsurgery. Intimal hyperplasia, lumen uniformity, graft stenosis, and graft perfusion were measured by intravascular ultrasound and angiography. Major cardiac and cerebrovascular events (MACCE; including death, myocardial infarction, stroke, and revascularization) were recorded over a median follow-up of 3 years. RESULTS: Worse lumen uniformity, greater stenosis, and worse graft perfusion were associated with higher IH values and an increased incidence of clinical events. Consistent with previous findings, we identified endoscopic vein harvesting, female sex, and transit time flow measurement of pulsatility index and flow as risk factors for SVG occlusion during the first year postsurgery. CONCLUSIONS: In this secondary analysis of the VEST trial, we observed an association between intimal hyperplasia area and clinical measures of SVG disease at 1 year postsurgery. More severe SVG disease and larger areas of IH were associated with a higher incidence of 3-year MACCE. Ongoing follow-up to 5 years will further elucidate the impact of SVG disease on long-term clinical outcomes of CABG.

Balancing quality and quaternary care imperative using a high-risk case review committee in adults.

OBJECTIVES: Quaternary care centres have an imperative to serve as hospitals of last resort and must also meet professional quality targets. We developed a high-risk committee (HRC) to evaluate cases meeting pre-defined predicted risk cut-offs as a part of an overall quality improvement drive. METHODS: We describe the structure, outcomes and effects of the Penn HRC. Using propensity-matching, we investigated whether the committee modifies or screens risk. We used multivariable analysis to examine the impact of unmeasured variables on clinical outcomes in this cohort. RESULTS: Institutional predicted and observed mortality had already been in decline prior to HRC institution in 2017, due to a multi-faceted quality improvement initiative. Between 2017 and 2020, the HRC discussed 205 patients with a median predicted risk of mortality of 10.6% (range 0.4-66%). Coronary artery bypass grafting was the most commonly presented operation. A total of 155 patients underwent operation (risk 10.3%), 12 had surgery deferred for optimization (risk 6%), 50 had surgery declined (risk 11.7%) and 12 patients had a deferred decision for further investigation. Overall 30-day survival was 86% for the entire cohort and 89% for operated patients. A matched analysis of similar patients prior to and following the HRC showed that the HRC did not directly modify outcomes. Most patients had better than expected survival (observed:expected mortality < 1). Predicted risk did not predict 30-day mortality among this high-risk cohort. CONCLUSIONS: HRCs serve as an important element in quality improvement by encouraging a thoughtful approach and channelling the collective experience of a group of senior surgeons. It may improve patient selection by identifying a cohort with extremely poor survival, while allowing safe operation with acceptable outcomes among a group with very high operative risk.

Topical nitroglycerin to detect reversible microcirculatory dysfunction in patients with circulatory shock after cardiovascular surgery: an observational study.

Persistent abnormalities in microcirculatory function are associated with poor clinical outcomes in patients with circulatory shock. We sought to identify patients with acutely reversible microcirculatory dysfunction using a low-dose topical nitroglycerin solution and handheld videomicroscopy during circulatory shock after cardiac surgery. Forty subjects were enrolled for the study, including 20 preoperative control and 20 post-operative patients with shock. To test whether microcirculatory dysfunction is acutely reversible during shock, the sublingual microcirculation was imaged with incident dark field microscopy before and after the application of 0.1 mL of a 1% nitroglycerin solution (1 mg/mL). Compared to the control group, patients with shock had a higher microcirculation heterogeneity index (MHI 0.33 vs. 0.12, p < 0.001) and a lower microvascular flow index (MFI 2.57 vs. 2.91, p < 0.001), total vessel density (TVD 22.47 vs. 25.90 mm/mm2, p = 0.005), proportion of perfused vessels (PPV 90.76 vs. 95.89%, p < 0.001) and perfused vessel density (PVD 20.44 vs. 24.81 mm/mm2, p < 0.001). After the nitroglycerin challenge, patients with shock had an increase in MFI (2.57 vs. 2.97, p < 0.001), TVD (22.47 vs. 27.51 mm/mm2, p < 0.009), PPV (90.76 vs. 95.91%, p < 0.001), PVD (20.44 vs. 26.41 mm/mm2, p < 0.001), venular RBC velocity (402.2 vs. 693.9 µm/s, p < 0.0004), and a decrease in MHI (0.33 vs. 0.04, p < 0.001. Thirteen of 20 patients showed a pharmacodynamic response, defined as an increase in PVD > 1.8 SD from shock baseline. Hemodynamics and vasoactive doses did not change during the 30-min study period. Our findings suggest a topical nitroglycerin challenge with handheld videomicroscopy can safely assess for localized recruitment of the microcirculatory blood flow in patients with circulatory shock and may be a useful test to identify nitroglycerin responsiveness.

Protocol for the MicroRESUS study: The impact of circulatory shock and resuscitation on microcirculatory function and mitochondrial respiration after cardiovascular surgery.

BACKGROUND: Despite current resuscitation strategies, circulatory shock and organ injury after cardiac surgery occur in 25-40% of patients. Goal-directed resuscitation after cardiac surgery has generated significant interest, but clinical practice to normalize hemodynamic variables including mean arterial pressure, cardiac filling pressures, and cardiac output may not reverse microcirculation abnormalities and do not address cellular dysoxia. Recent advances in technology have made it possible to measure critical components of oxygen delivery and oxygen utilization systems in live human tissues and blood cells. The MicroRESUS study will be the first study to measure microcirculatory and mitochondrial function in patients with circulatory shock and link these findings with clinical outcomes. METHODS AND ANALYSIS: This will be a prospective, observational study that includes patients undergoing elective cardiovascular surgery with cardiopulmonary bypass (CPB). Microcirculation will be quantified with sublingual incident dark field videomicroscopy. Mitochondrial respiration will be measured by performing a substrate-uncoupler-inhibitor titration protocol with high resolution respirometry on peripheral blood mononuclear cells at baseline and serial timepoints during resuscitation and at recovery as a possible liquid biomarker. Plasma samples will be preserved for future analysis to examine endothelial injury and other mechanisms of microcirculatory dysfunction. Thirty-day ventilator and vasopressor-free days (VVFDs) will be measured as a primary outcome, along with sequential organ failure assessment scores, and other clinical parameters to determine if changes in microcirculation and mitochondrial respiration are more strongly associated with clinical outcomes compared to traditional resuscitation targets. DISCUSSION: This will be the first prospective study to examine both microcirculatory and mitochondrial function in human patients with circulatory shock undergoing cardiac bypass and address a key mechanistic knowledge gap in the cardiovascular literature. The results of this study will direct future research efforts and therapeutic development for patients with shock.

Safety and Effectiveness of Intravenous Iron Therapy in Patients Supported by Durable Left Ventricular Assist Devices.

AIMS: While it is common practice to use intravenous (IV) iron in patients with left ventricular assist devices (LVADs) and iron deficiency, there is insufficient evidence regarding outcomes in this patient population. We evaluated the safety and effectiveness of IV iron therapy in patients supported by LVADs with iron deficiency. METHODS: We performed a retrospective analysis of iron deficient patients on continuous LVAD support at a large academic center between 2008 and 2019. Patients were divided into two cohorts based on IV iron sucrose treatment. The primary endpoint was hemoglobin at 12 weeks. Secondary endpoints were mean corpuscular volume (MCV) and New York Heart Association (NYHA) class at 12 weeks. Safety endpoints included hospitalization, infection, pump thrombosis, arrhythmia, and gastrointestinal bleed. Models were weighted by the inverse probability of receiving IV iron using a propensity score, and endpoints were adjusted for their corresponding baseline values. RESULTS: Among 213 patients, 70 patients received IV iron and 143 patients did not. Hemoglobin at 12 weeks was significantly greater among those treated (intergroup difference: 0.6 g/dL; 95% CI, 0.1 to 1.1; p = 0.01), while MCV was similar in both groups (intergroup difference: 0.7 µm3; 95% CI, -1.3 to 2.7; p = 0.50). NYHA class distribution at 12 weeks was significantly different (odds ratio for improvement: 2.84; 95% CI, 1.42 to 4.68; p = 0.003). The hazards of adverse events in each group were similar. CONCLUSIONS: In patients with LVADs and iron deficiency, treatment with IV iron sucrose was safe and associated with improvements in functional status and hemoglobin.

External Support for Saphenous Vein Grafts in Coronary Artery Bypass Surgery: A Randomized Clinical Trial.

Importance: Intimal hyperplasia and subsequent saphenous vein graft failure may have significant adverse clinical effects in patients undergoing coronary artery bypass surgery. External support of saphenous vein grafts has the potential to prevent vein graft dilation and hence slow the rate of intimal hyperplasia and increase long-term vein patency. Objective: To determine efficacy, as measured by intimal hyperplasia, and safety of an external saphenous vein graft support device in patients undergoing a coronary bypass graft procedure. Design, Setting, and Participants: This within-patient randomized, open-label, multicenter study was conducted at 17 Cardiothoracic Surgical Trials Network centers in North America. Between January 2018 and February 2019, 224 patients with multivessel coronary artery disease undergoing isolated bypass surgery were enrolled. For each patient, 1 of 2 vein grafts was randomized to receive external support or no support. Interventions: External vein graft support or no support. Main Outcomes and Measures: The primary efficacy end point was intimal hyperplasia area assessed by intravascular ultrasound at 12 months postrandomization for each study graft. Secondary confirmatory end points were lumen diameter uniformity assessed by angiography and graft failure (≥50% stenosis) by quantitative coronary angiography. Major cardiac and cerebrovascular events were collected through month 12. Results: Among 224 patients (mean [SD] age, 65.8 [8.3] years; 178 [79.5%] male), 203 (90.6%) were eligible for intravascular ultrasound, of which 85 (41.9%) had at least 1 study graft occluded or severely diseased at 12 months (55 supported, 56 unsupported). After imputation of data missing because of graft occlusion or severe disease, the estimated mean (SE) intimal hyperplasia area was 5.11 (0.16) mm2 in supported grafts and 5.79 (0.20) mm2 in unsupported grafts (P = .07). In a sensitivity analysis of 113 patients with both grafts imaged, the mean intimal hyperplasia area was 4.58 (0.18) mm2 and 5.12 (0.23) mm2 in supported and unsupported grafts, respectively (P = .04). By 12 months, 5 patients (2.2%) died and 16 patients (7.1%) experienced a major cardiac or cerebrovascular event. Conclusions and Relevance: The 12-month difference in intimal hyperplasia area between supported and unsupported grafts did not achieve statistical significance. Cumulative mortality and major cardiac or cerebrovascular events rates were similar to those in other randomized coronary artery bypass trials. Further investigation to assess the effect of external graft support devices on long-term graft patency and clinical outcomes is warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT03209609.

Delays in the Identification and Assessment of in-Hospital Stroke Patients.

OBJECTIVES: In-hospital stroke is associated with poor outcomes. Reasons for delays, use of interventions, and presence of large vessel occlusion are not well characterized. MATERIALS AND METHODS: A retrospective single center cohort of 97 patients with in-hospital stroke was analyzed to identify factors associated with delays from last known normal to symptom identification and to stroke team alerting. Stroke interventions and presence of large vessel occlusion were also assessed. RESULTS: Strokes were predominantly on surgery services (70%), ischemic (82%), and severe (median NIHSS 16; interquartile range [IQR] 6-24). There were long delays from last known normal to symptom identification (median 5.1 hours, IQR 1.0-19.7 hours), symptom identification to stroke team alerting (median 2.1 hours, IQR 0.5-9.9 hours), and total time from last known normal to alerting (median 11.4 [IQR 2.7-34.2] hours). In univariable analysis, being on a surgical service, in an ICU, intubated, and higher NIHSS were associated with delays. In multivariable analysis only intubation was independently associated with time from last known normal to symptom identification (coefficient 20 hours, IQR 0.2 - 39.8, p=0.047). Interventions were given to 17/80 (21%) ischemic stroke patients; 3 (4%) received IV tPA and 14 (18%) underwent thrombectomy. Vascular imaging occurred in 57/80 (71%) ischemic stroke patients and 21/57 (37%) had large vessel occlusion. CONCLUSIONS: Hospitalized patients with stroke experience long delays from symptom identification to stroke team alerting. Intubation was strongly associated with delay to symptom identification. Although stroke severity was high and large vessel occlusion common, many patients did not receive acute interventions.

Optimal Surgical Approach to Left Atrioesophageal Fistula After Catheter Radiofrequency Ablation.

Atrioesophageal fistula formation is a rare but formidable complication after catheter radiofrequency ablation for atrial fibrillation. We present 4 patients who underwent urgent primary intracardiac repair of the left atrium via sternotomy with central cardiopulmonary bypass and early aortic cross-clamp, followed by repair of the esophagus. We believe that this approach represents the safest strategy for addressing this morbid and often fatal complication.

Transparency, Public Reporting, and a Culture of Change to Quality and Safety in Cardiac Surgery.

Academic medical centers have a duty to serve as hospitals of last resort for advanced cardiac surgical care and therefore manage patients at elevated risk of postoperative morbidity and mortality. They must also meet state and professional quality targets devised to protect the public. The tension between these imperatives can be managed by a multidimensional quality improvement program that aims to manage risk, optimize outcomes, and exclude futile operations. We here share our approach to this process, its impact on our institution, and discuss pertinent issues relevant to institutions in a similar situation.

Rationale and design of a randomized trial evaluating an external support device for saphenous vein coronary grafts.

BACKGROUND: Coronary artery bypass grafting (CABG) is the most common revascularization approach for the treatment of multi-vessel coronary artery disease. While the internal mammary artery is nearly universally used to bypass the left anterior descending coronary artery, autologous saphenous vein grafts (SVGs) are still the most frequently used conduits to grafts the remaining coronary artery targets. Long-term failure of these grafts, however, continues to limit the benefits of surgery. METHODS: The Cardiothoracic Surgical Trials Network trial of the safety and effectiveness of a Venous External Support (VEST) device is a randomized, multicenter, within-patient trial comparing VEST-supported versus unsupported saphenous vein grafts in patients undergoing CABG. Key inclusion criteria are the need for CABG with a planned internal mammary artery to the left anterior descending and two or more saphenous vein grafts to other coronary arteries. The primary efficacy endpoint of the trial is SVG intimal hyperplasia (plaque + media) area assessed by intravascular ultrasound at 12 months post randomization. Occluded grafts are accounted for in the analysis of the primary endpoint. Secondary confirmatory endpoints are lumen diameter uniformity and graft failure (>50% stenosis) assessed by coronary angiography at 12 months. The safety endpoints are the occurrence of major adverse cardiac and cerebrovascular events and hospitalization within 5 years from randomization. CONCLUSIONS: The results of the VEST trial will determine whether the VEST device can safely limit SVG intimal hyperplasia in patients undergoing CABG as treatment for coronary atherosclerotic disease.

Clinical and Echocardiographic Results of Aortic Valve Replacement in the Failing Ventricle: Do Aortic Stenosis and Aortic Regurgitation Differ?

BACKGROUND: We hypothesized that long-term clinical and echocardiographic recovery of the impaired ventricle from pressure (aortic stenosis [AS]) and volume (aortic regurgitation [AR]) overload would be different after aortic valve replacement (AVR). METHODS: We compared the results of AVR in patients with a preoperative ejection fraction (EF) of 0.35 or less due to AS, AR, or mixed disease. We constructed a mixed-effects model of EF and left ventricular (LV) end-diastolic diameter (LVEDD) to understand ventricular recovery over the short- (in-hospital), intermediate- (3-6 months), and longer- (>24 months) terms. We sought to identify factors associated with clinical and echocardiographic recovery using multivariable analysis. RESULTS: Between July 2011 and 2017, 136 patients with a preoperative EF of 0.35 or less and severe AS (n = 83), severe AR (n = 18), or mixed AS and AR (n = 35) underwent AVR. There were 2 (1.5%) early deaths in the AS group. Survival at 1, 2, and 5 years did not differ between groups. Baseline EF did not differ between the groups but improved with markedly different trajectory and time course in the AS, AR, and mixed groups over time. LVEDD regressed in all patient cohorts, following a different pattern for AS and AR. Baseline EF and LVEDD predicted the long-term fate of the LV but did not determine survival. We identify factors associated with long-term survival. CONCLUSIONS: The pattern of LV recovery appears to be early in AS and delayed in AR. Baseline clinical factors, rather than echocardiographic status of the LV, appear to determine late survival.

Correlating oxygen delivery on cardiopulmonary bypass with Society of Thoracic Surgeons outcomes following cardiac surgery.

BACKGROUND: The relationship between low oxygen delivery (DO2) on cardiopulmonary bypass and morbidity and mortality following cardiac surgery remains unexamined. METHODS: We reviewed patients undergoing Society of Thoracic Surgeons index procedures from March 2019 to July 2020, coincident with implementation of a new electronic perfusion record that provides for continuous recording of DO2 and flow parameters. Continuous perfusion variables were analyzed using area-over-the-curve (AOC) calculations below predefined thresholds (DO2 <280 mL O2/min/m2, cardiac index <2.2 L/min, hemoglobin < baseline, and mean arterial pressure <65 mm Hg) to quantify depth and duration of potentially harmful exposures. Multivariable logistic regression adjusted by Society of Thoracic Surgeons predicted-risk scores were used to assess for relationship of perfusion variables with the primary composite outcome of any Society of Thoracic Surgeons index procedure, as well as individual Society of Thoracic Surgeons secondary outcomes (eg, mortality, renal failure, prolonged ventilation >24 hours, stroke, sternal wound infection, and reoperation). RESULTS: Eight hundred thirty-four patients were included; 42.7% (356) underwent isolated coronary artery bypass grafting (CABG), whereas 57.3% underwent nonisolated CABG (eg, valvular or combined CABG/valvular operations). DO2 <280-AOC trended toward association with the primary outcome across all cases (P = .07), and was significantly associated for all nonisolated CABG cases (P = .02)-more strongly than for cardiac index <2.2-AOC (P = .04), hemoglobin <7-AOC (P = .51), or mean arterial pressure <65-AOC (P = .11). Considering all procedures, DO2 <280-AOC was independently associated prolonged ventilation >24 hours (P = .04), an effect again most pronounced in nonisolated-CABG cases (P = .002), as well as acute kidney injury <72 hours (P = .04). Patients with glomerular filtration rate <65 mL/min and baseline hemoglobin <12.5 g/dL appeared especially vulnerable. CONCLUSIONS: Low DO2 on bypass may be associated with morbidity/mortality following cardiac surgery, particularly in patients undergoing nonisolated CABG. These results underscore the importance of goal-directed perfusion strategies.

Safety of Intravenous Cangrelor Administration for Antiplatelet Bridging in Hospitalized Patients: A Retrospective Study.

OBJECTIVE: We aimed to characterize outcomes associated with cangrelor administration used in an antiplatelet bridging strategy in real-world clinical scenarios within a large academic medical system. BACKGROUND: Cangrelor has been used for antiplatelet bridging in perioperative settings or for patients unable to take oral medications. Prior studies in these settings have reported bleeding rates from 0%-40%. METHODS: Patients were retrospectively identified via chart review and included if they were over 18 years old, had coronary or peripheral arterial stents, and had received at least 1 hour of cangrelor infusion during inpatient admission. The primary endpoint was Bleeding Academic Research Consortium (BARC) 3-5 bleeding during cangrelor infusion or within 48 hours of discontinuation; secondary endpoints were bleeding events defined by Thrombolysis in Myocardial Infarction (TIMI), Global Use of Strategies to Open Occluded Arteries (GUSTO), and International Society on Thrombosis and Hemostasis (ISTH) criteria, as well as BARC 2 bleeding. RESULTS: Thirty-one patients met the inclusion criteria. Cangrelor indications were bridging to procedure in 22 patients (71.0%) and inability to take oral P2Y12 inhibitors in 9 patients (29.0%). Twenty-three patients (74.2%) were men, 11 patients (35.5%) were in cardiogenic shock, and 4 patients (12.9%) were on extracorporeal membrane oxygenation (ECMO) at the time of administration. No patients received cangrelor for routine percutaneous coronary intervention. Of the 31 patients, 13 (41.9%) had BARC 3-5 bleeding and 7 (22.6%) expired during hospitalization. All 4 patients on ECMO suffered BARC 3-5 bleeding. CONCLUSIONS: We reviewed the use of cangrelor for antiplatelet bridging in real-world clinical scenarios and observed higher rates of clinically significant bleeding than seen in other similar studies. Our study suggests careful consideration when using cangrelor in a sick patient population.

Mitral Surgery After Transcatheter Edge-to-Edge Repair: Society of Thoracic Surgeons Database Analysis.

BACKGROUND: Transcatheter edge-to-edge (TEER) mitral repair may be complicated by residual or recurrent mitral regurgitation. An increasing need for surgical reintervention has been reported, but operative outcomes are ill defined. OBJECTIVES: This study evaluated national outcomes of mitral surgery after TEER. METHODS: The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database was used to identify 524 adults who underwent mitral surgery after TEER between July 2014 and June 2020. Emergencies (5.0%; n = 26), previous mitral surgery (5.3%; n = 28), or open implantation of transcatheter prostheses (1.5%; n = 8) were excluded. The primary outcome was 30-day or in-hospital mortality. RESULTS: In the study cohort of 463 patients, the median age was 76 years (interquartile range [IQR]: 67 to 81 years), median left ventricular ejection fraction was 57% (IQR: 48% to 62%), and 177 (38.2%) patients had degenerative disease. Major concomitant cardiac surgery was performed in 137 (29.4%) patients: in patients undergoing isolated mitral surgery, the median STS-predicted mortality was 6.5% (IQR: 3.9% to 10.5%), the observed mortality was 10.2% (n = 23 of 225), and the ratio of observed to expected mortality was 1.2 (95% confidence interval [CI]: 0.8 to 1.9). Predictors of mortality included urgent surgery (odds ratio [OR]: 2.4; 95% CI: 1.3 to 4.6), nondegenerative/unknown etiology (OR: 2.2; 95% CI: 1.1 to 4.5), creatinine of >2.0 mg/dl (OR: 3.8; 95% CI: 1.9 to 7.9) and age of >80 years (OR: 2.1; 95% CI: 1.1 to 4.4). In a volume outcomes analysis in an expanded cohort of 591 patients at 227 hospitals, operative mortality was 2.6% (n = 2 of 76) in 4 centers that performed >10 cases versus 12.4% (n = 64 of 515) in centers performing fewer (p = 0.01). The surgical repair rate after failed TEER was 4.8% (n = 22) and was 6.8% (n = 12) in degenerative disease. CONCLUSIONS: This study indicates that mitral repair is infrequently achieved after failed TEER, which may have implications for treatment choice in lower-risk and younger patients with degenerative disease. These findings should inform patient consent for TEER, clinical trial design, and clinical performance measures.