A Pilot Study Using Machine Learning Algorithms and Wearable Technology for the Early Detection of Postoperative Complications After Cardiothoracic Surgery.

OBJECTIVE: To evaluate whether a machine learning algorithm (i.e. the "NightSignal" algorithm) can be used for the detection of postoperative complications prior to symptom onset after cardiothoracic surgery. SUMMARY BACKGROUND DATA: Methods that enable the early detection of postoperative complications after cardiothoracic surgery are needed. METHODS: This was a prospective observational cohort study conducted from July 2021 to February 2023 at a single academic tertiary care hospital. Patients aged 18 years or older scheduled to undergo cardiothoracic surgery were recruited. Study participants wore a Fitbit watch continuously for at least 1 week preoperatively and up to 90-days postoperatively. The ability of the NightSignal algorithm-which was previously developed for the early detection of Covid-19-to detect postoperative complications was evaluated. The primary outcomes were algorithm sensitivity and specificity for postoperative event detection. RESULTS: A total of 56 patients undergoing cardiothoracic surgery met inclusion criteria, of which 24 (42.9%) underwent thoracic operations and 32 (57.1%) underwent cardiac operations. The median age was 62 (IQR: 51-68) years and 30 (53.6%) patients were female. The NightSignal algorithm detected 17 of the 21 postoperative events a median of 2 (IQR: 1-3) days prior to symptom onset, representing a sensitivity of 81%. The specificity, negative predictive value, and positive predictive value of the algorithm for the detection of postoperative events were 75%, 97%, and 28%, respectively. CONCLUSIONS: Machine learning analysis of biometric data collected from wearable devices has the potential to detect postoperative complications-prior to symptom onset-after cardiothoracic surgery.

Rationale and Design of the Randomized Controlled Trial of New Oral Anticoagulants Versus Warfarin for Post Cardiac Surgery Atrial Fibrillation: The NEW-AF Trial.

OBJECTIVE: This manuscript describes the rationale and design of a randomized, controlled trial comparing outcomes with Warfarin vs Novel Oral Anticoagulant (NOAC) therapy in patients with new onset atrial fibrillation after cardiac surgery. BACKGROUND: New onset atrial fibrillation commonly occurs after cardiac surgery and is associated with increased rates of stroke and mortality. in nonsurgical patients with atrial fibrillation, NOACs have been shown to confer equivalent benefits for stroke prevention with less bleeding risk and less tedious monitoring requirements compared with Warfarin. However, NOAC use has yet to be adopted widely in cardiac surgery patients. METHODS: The NEW-AF study has been designed as a pragmatic, prospective, randomized controlled trial that will compare financial, convenience and safety outcomes for patients with new onset atrial fibrillation after cardiac surgery that are treated with NOACs versus Warfarin. RESULTS: Study results may contribute to optimizing the options for stroke prophylaxis in cardiac surgery patients and catalyze more widespread application of NOAC therapy in this patient population. CONCLUSIONS: The study is ongoing and actively enrolling at the time of the publication. The trial is registered with clinicaltrials.gov under registration number NCT03702582.

Differences in Aortic Intramural Hematoma Contrast Attenuation on Multi-Phase CTA Predict Long-Term Aortic Morphologic Change.

BACKGROUND: Evolution of aortic intramural hematoma (IMH) over time may range from resolution to degeneration and is difficult to predict. We sought to measure differences in contrast attenuation between arterial and delayed phase computed tomography angiography (CTA) images within the IMH as a surrogate of hematoma blood flow to predict resolution versus aortic growth and/or adverse outcomes. METHODS: IMH institutional data were gathered from 2005-2020. Hounsfield unit ratio (HUR) was measured as hematoma Hounsfield unit (HU), on delayed phase images divided by HU on arterial phase images on CTA. Aortic growth and effect of HUR was determined using a linear mixed effects model. Freedom from adverse aortic event, defined as the composite of intervention, recurrence of symptoms, radiographic progression, and rupture, was determined using Kaplan-Meier analysis. RESULTS: IMH occurred in 73 patients, of which 27 met the inclusion criteria. HUR ranged from 0.38-1.92 (mean: 0.98). Baseline aortic diameter growth independent of HUR measurement was 0.49 mm/year (95% confidence interval CI: -1.23 to 2.2). With the HUR was introduced into the model, the beta coefficient for time was -5.83 mm/year (95% CI: -10.4 to -1.28 mm/year) and the beta coefficient for the HUR was 5.05 mm/year per one-unit HUR (95% CI: 0.56 to 9.56 mm/year). Thus, an HUR>1.15 would correspond to aortic growth while an HUR<1.15 would correspond to reduction in aortic diameter, consistent with IMH resolution. Aortic adverse events occurred in 13 (48%) patients, 7 (26%) patients had recurrence of symptoms, 8 (30%) required intervention, 5 (18%) progressed to dissection, and 1(4%) had aortic rupture. There was a trend towards an association between higher HUR and composite adverse aortic events (HR 3.2 per 1-unit HUR; 95% CI: 0.6-17.3; P = 0.18). CONCLUSIONS: Increased HUR is associated with increased aortic growth and a trend toward adverse aortic events. Diminished delayed phase enhancement may predict partial or complete IMH resolution. HUR can be used to guide IMH surveillance and treatment.

Role of advanced imaging techniques in cardiac surgery: Aortic dissection.

BACKGROUND: Collaboration among cardiac surgeons and radiologists is essential to fully leverage advanced imaging technologies and improve the care of cardiac surgery patients. In this review, a cardiac surgeon and cardiovascular radiologist discuss imaging pearls and considerations in aortic dissection cases. METHODS: The surgeon and the radiologist discuss imaging considerations in two aortic dissection cases. RESULTS: It is essential to obtain and review all phases of a CTA when diagnosing acute aortic pathology. Optimizing scan parameters and careful multiplanar image review is necessary for adept interpretation. Current CT technology allows ECG gating to eliminate motion artifact and allow for dynamic assessment of the aortic pathology. Concurrent evaluation of thoracic aorta and coronary arteries is feasible. A systematic review of the scan using landmarks is critical for appropriate diagnosis and reporting. As TEVAR is increasingly used for arch repair, collaboration with radiologists is essential for preoperative planning in redo cases. CONCLUSIONS: Collaboration among cardiac surgeons and radiologists is mutually beneficial for surgeons, radiologists, and their patients.

Late onset atrial fibrillation in patients undergoing surgical aortic valve replacement.

OBJECTIVE: Aortic valve disease is a risk factor for atrial fibrillation (AF), and AF is associated with increased late mortality and morbidity after cardiac surgery. The evolution of alternative approaches to AF prophylaxis, including less invasive technologies and medical therapies, has altered the balance between risk and potential benefit for prophylactic intervention at the time of surgical aortic valve replacement (SAVR). Such interventions impose incremental risk, however, making an understanding of predictors of new onset AF that persists beyond the perioperative episode relevant. METHODS: We conducted a retrospective single-institution cohort analysis of patients undergoing SAVR with no history of preoperative AF (n = 1014). These patients were cross-referenced against an institutional electrocardiogram (ECG) database to identify those with ECGs 3-12 months after surgery. Logistic regression was used to identify predictors of late AF. RESULTS: Among the 401 patients (40%), who had ECGs in our institution 3-12 months after surgery, 16 (4%) had late AF. Patients with late AF were older than patients without late AF (73 vs. 65, p = .025), and underwent procedures that were more urgent/emergent (38% vs. 15%, p = .015), with higher predicted risk of mortality (2.2% vs. 1.3%, p = .012). Predictors associated with the development of late AF were advanced age, higher preoperative creatinine level and urgent/emergent surgery. CONCLUSIONS: The incidence of late AF 3-12 months after SAVR, is low. Prophylactic AF interventions at the time of SAVR may not be warranted.

Risk factors for ischemic gastrointestinal complications in patients undergoing open cardiac surgical procedures: A single-center retrospective experience.

BACKGROUND: Ischemic gastrointestinal complications (IGIC) following cardiac surgery are associated with high morbidity and mortality and remain difficult to predict. We evaluated perioperative risk factors for IGIC in patients undergoing open cardiac surgery. METHODS: All patients that underwent an open cardiac surgical procedure at a tertiary academic center between 2011 and 2017 were included. The primary outcome was IGIC, defined as acute mesenteric ischemia necessitating a surgical intervention or postoperative gastrointestinal bleeding that was proven to be of ischemic etiology and necessitated blood product transfusion. A backward stepwise regression model was constructed to identify perioperative predictors of IGIC. RESULTS: Of 6862 patients who underwent cardiac surgery during the study period, 52(0.8%) developed IGIC. The highest incidence of IGIC (1.9%) was noted in patients undergoing concomitant coronary artery, valvular, and aortic procedures. The multivariable regression identified hypertension (odds ratio [OR] = 5.74), preoperative renal failure requiring dialysis (OR = 3.62), immunocompromised status (OR = 2.64), chronic lung disease (OR = 2.61), and history of heart failure (OR = 2.03) as independent predictors for postoperative IGIC. Pre- or intraoperative utilization of intra-aortic balloon pump or catheter-based assist devices (OR = 4.54), intraoperative transfusion requirement of >4 RBC units(OR = 2.47), and cardiopulmonary bypass > 180 min (OR = 2.28) were also identified as independent predictors for the development of IGIC. CONCLUSIONS: We identified preoperative and intraoperative risk factors that independently increase the risk of developing postoperative IGIC after cardiac surgery. A high index of suspicion must be maintained and any deviation from the expected recovery course in patients with the above-identified risk factors should trigger an immediate evaluation with the involvement of the acute care surgical team.

Teamwork in the time of coronavirus: An MGH experience.

The global pandemic of coronavirus 2019 (COVID-19) caused by coronavirus has had a profound impact on the delivery of health care in the United States and globally. Boston was among the earliest hit cities in the United States, and within Boston, the Massachusetts General Hospital provided care for more patients with COVID-19 than any other hospital in the region. This necessitated a massive reallocation of resources and priorities, with a near doubling of intensive care bed capacity and a halt in all deferrable surgical cases. During this crisis, the Division of Cardiac Surgery responded in a unified manner, dealing honestly with the necessity to reduce Intensive Care Unit resource utilization for the benefit of both the institution and our community by deferring nonemergent cases while also continuing to efficiently care for those patients in urgent or emergent need of surgery. Many of the interventions that we instituted have continued to support teamwork as we adapt to the remarkably fluid changes in resource availability during the recovery phase. We believe that the culture of our division and the structure of our practice facilitated our ability to contribute to the mission of our hospital to support the community in this crisis, and now to its recovery. We describe here the challenge we faced in Boston and some of the details of the structure and function of our division.

STratification risk analysis in OPerative management (STOP score) for drug-induced endocarditis.

BACKGROUND: The opioid epidemic has seen a drastic increase in the incidence of drug-associated infective endocarditis (IE). No clinical tool exists to predict operative morbidity and mortality in patients undergoing surgery. METHODS: A multi-institutional database was reviewed between 2011 and 2018. Multivariate logistic regression was fitted in an automated stepwise fashion. The STratification risk analysis in OPerative management of drug-associated IE (STOP) score was constructed. Morbidity was defined as reintubation, prolonged ventilation, pneumonia, renal failure, dialysis, stroke, reoperation for bleeding, and a permanent pacemaker. Cross-validation provided an unbiased estimate of out-of-sample performance. RESULTS: A total of 1181 patients underwent surgery for drug-associated IE (median age, 39; interquartile range [IQR], 30-54, 386 women [32.7%], 341 reoperations for prosthetic valve endocarditis [28.9%], 316 patients with multivalve disease [26.8%]). Operative morbidity and mortality were 41.1% and 5.9%, respectively. Predictors of morbidity were dialysis (95% confidence interval [CI], 1.16-2.82), emergent intervention (1.83-4.73), multivalve procedure (1.01-1.98), causative organisms other than Streptococcus (1.09-2.02), and type of valve procedure performed [aortic valve procedure (1.07-2.15), mitral valve replacement (1.03-2.05), tricuspid valve replacement (1.21-2.60)]. Predictors of mortality were dialysis (1.29-5.74), active endocarditis (1.32-83), lung disease (1.25-5.43), emergent intervention (1.69-6.60), prosthetic valve endocarditis (1.24-3.69), aortic valve procedure (1.49-5.92) and multivalve disease (1.00-2.95). Variables maximizing explanatory power were translated into a scoring system. Each point increased odds of morbidity and mortality by 22.0% and 22.4% with an accuracy of 94.0% and 94.1%, respectively. CONCLUSION: Drug-related IE is associated with significant morbidity and mortality. An easily-applied risk stratification score may aid in clinical decision-making.

Type A aortic dissection in the East and West: A comparative study between two hospitals from China and the US.

BACKGROUND: In this study, we compare the clinical characteristics, intraoperative management, and postoperative outcomes of patients with acute type A aortic dissection (ATAAD) between two academic medical hospitals in the United States and China. METHODS: From January 2011 to December 2017, 641 and 150 patients from Nanjing Drum Tower Hospital (NDTH) and Massachusetts General Hospital (MGH) were enrolled. Patient demographics, clinical features, surgical techniques, and postoperative outcomes were compared. RESULTS: The annual number of patients presenting with ATAAD at MGH remained relatively stable, while the number at NDTH increased significantly over the study period. The average age was 51 years at NDTH and 61 years at MGH (P < .001). The percentage of patients with known hypertension at the two centers was similar. The time interval from onset of symptoms to diagnosis was significantly longer at NDTH than MGH (11 vs 3.5 hours; P < .001). Associated complications at presentation were more common at NDTH than MGH. More than 90% of patients (91% NDTH and 92% MGH) underwent surgery. The postoperative stroke rate was higher at MGH (12% vs 4%; P < .001); however, the 30-day mortality rate was lower (7% vs 16%; P = .006). CONCLUSIONS: There was a significant increase in the number of ATAAD at NDTH during the study period while the number at MGH remained stable. Hypertension was a common major risk factor; however, the onset of ATAAD at NDTH was nearly one decade earlier than MGH. Chinese patients tended to have more complicated preoperative pathophysiology at presentation and underwent more extensive surgical repair.

Quantitative three-dimensional echocardiographic analysis of the bicuspid aortic valve and aortic root: A single modality approach.

BACKGROUND: Patients with bicuspid aortic valves (BAV) are heterogeneous with regard to patterns of root remodeling and valvular dysfunction. Two-dimensional echocardiography is the standard surveillance modality for patients with aortic valve dysfunction. However, ancillary computed tomography or magnetic resonance imaging is often necessary to characterize associated patterns of aortic root pathology. Conversely, the pairing of three-dimensional (3D) echocardiography with novel quantitative modeling techniques allows for a single modality description of the entire root complex. We sought to determine 3D aortic valve and root geometry with this quantitative approach. METHODS: Transesophageal real-time 3D echocardiography was performed in five patients with tricuspid aortic valves (TAV) and in five patients with BAV. No patient had evidence of valvular dysfunction or aortic root pathology. A customized image analysis protocol was used to assess 3D aortic annular, valvular, and root geometry. RESULTS: Annular, sinus and sinotubular junction diameters and areas were similar in both groups. Coaptation length and area were higher in the TAV group (7.25 ± 0.98 mm and 298 ± 118 mm2 , respectively) compared to the BAV group (5.67 ± 1.33 mm and 177 ± 43 mm2 ; P = .07 and P = .01). Cusp surface area to annular area, coaptation height, and the sub- and supravalvular tenting indices did not differ significantly between groups. CONCLUSIONS: Single modality 3D echocardiography-based modeling allows for a quantitative description of the aortic valve and root geometry. This technique together with novel indices will improve our understanding of normal and pathologic geometry in the BAV population and may help to identify geometric predictors of adverse remodeling and guide tailored surgical therapy.

Early structural valve deterioration and reoperation associated with the mitroflow aortic valve.

BACKGROUND: Structural valve deterioration (SVD) is a known limitation of bioprosthetic valves. Recent reports have suggested a concerning rate of early SVD in patients receiving a Mitroflow aortic bioprosthesis. We therefore compared the incidence of SVD and SVD requiring reoperation among patients receiving a Mitroflow versus a common contemporary bioprosthesis. METHODS: A retrospective cohort analysis was performed on 592 patients receiving a Mitroflow aortic bioprosthesis at our institution between 2010 and 2014. Patients were matched 1:1 using a coarsened exact matching algorithm with patients receiving a Carpentier-Edwards Magna Ease aortic bioprosthesis (Edwards Lifesciences, Irvine, CA) during the same period. The incidence of SVD (defined as a mean transprosthetic gradient ≥30 mmHg or moderate to severe intraprosthetic regurgitation), reoperation for SVD, and cumulative survival were compared between prosthesis types. RESULTS: The cumulative incidence of SVD at 5 years for all patients receiving a Mitroflow aortic bioprosthesis was 16% (13-21%) and 5% underwent reoperation for SVD. Implantation of a Mitroflow valve was associated with an increased risk of SVD compared to the comparator valve (hazard ratio [HR] 2.59 [1.69-3.98], P < 0.01). Older age had a protective effect against SVD (HR 0.95 [0.93-0.96], P < 0.01). Patients who received a Mitroflow valve had reduced long-term survival compared to those who received a comparator valve (P = 0.03). CONCLUSION: The Mitroflow aortic bioprosthesis is associated with increased rates of early SVD and reoperation for valvular dysfunction as well as reduced survival compared to a contemporary valve. Enhanced clinical and echocardiographic follow-up is advisable after Mitroflow implantation.

Incidental moderate mitral regurgitation in patients undergoing aortic valve replacement for aortic stenosis: review of guidelines and current evidence.

Recent evidence has shown that moderate mitral regurgitation is common and clinically relevant in patients presenting for surgical and transcatheter aortic valve replacement for aortic stenosis. Prospective multicenter clinical trials are now indicated to resolve the clinical equipoise about whether or not mitral valve intervention also is indicated at the time of aortic valve intervention. Advances in three-dimensional transesophageal echocardiography, transcatheter mitral interventions, and surgical aortic valve replacement, including the advent of sutureless valves, likely will expand the therapeutic possibilities for moderate mitral regurgitation in the setting of aortic valve interventions for severe aortic stenosis.

Outcomes of Transcatheter Aortic Valve Replacement Using Third-Generation Balloon-Expandable Versus Self-Expanding Valves: A Meta-analysis.

Background: The choice of transcatheter aortic valve replacement (TAVR) prosthesis is crucial in optimizing short- and long-term outcomes. The objective of this study was to conduct a meta-analysis comparing outcomes of third-generation balloon-expandable valves (BEV) vs self-expanding valves (SEV). Methods: Electronic databases were searched from inception to June 2023 for studies comparing third-generation BEV vs SEV. Primary outcome was all-cause mortality. Secondary outcomes included clinical and hemodynamic end points. Random-effects models were used to calculate pooled odds ratios (ORs) or weighted mean differences (WMDs). Results: The meta-analysis included 16 studies and 10,174 patients (BEV, 5753 and SEV, 4421). There were no significant differences in 1-year all-cause mortality (OR, 1.15; 95% CI, 0.89-1.48) between third-generation BEV vs SEV. TAVR with third generation BEV was associated with a significantly lower risk of TIA/stroke (OR, 0.62; 95% CI, 0.44-0.87), permanent pacemaker implantation (OR, 0.55; 95% CI, 0.44-0.70), and ≥moderate paravalvular leak (PVL, OR, 0.43; 95% CI, 0.25-0.75), and higher risk of ≥moderate patient-prosthesis mismatch (OR, 3.76; 95% CI, 2.33-6.05), higher mean gradient (WMD, 4.35; 95% CI, 3.63-5.08), and smaller effective orifice area (WMD, -0.30; 95% CI, -0.37 to -0.23), compared with SEV. Conclusion: In this meta-analysis, TAVR with third-generation BEV vs SEV was associated with similar all-cause mortality, lower risk of TIA/stroke, permanent pacemaker implantation, and ≥moderate PVL, but higher risk of ≥moderate patient-prosthesis mismatch, higher mean gradient, and smaller effective orifice area. Large, adequately powered randomized trials are needed to evaluate long-term outcomes of TAVR with latest generations of BEV vs SEV.

Sutureless Valves, a "Wireless" Option for Patients With Aortic Valve Disease: JACC State-of-the-Art Review.

Transcatheter technologies triggered the recent revision of the guidelines that progressively widened the indications for the treatment of aortic stenosis. On the surgical realm, a technology avoiding the need for sutures to anchor the prosthesis to the aortic annulus has been developed with the aim to reduce the duration of cardiopulmonary bypass and simplify the process of valve implantation. In addition to a transcatheter aortic valve replacement (TAVR)-like stent that exerts a radial force, these so-called "rapid deployment valves" or "sutureless valves" for aortic valve replacement also have cuffs to improve sealing and reduce the risk of paravalvular leak. Despite promising, the actual advantage of sutureless valves over traditional surgical procedures (surgical aortic valve replacement) or TAVR is still debated. This review summarizes the current comparative evidence reporting outcomes of "sutureless valves" for aortic valve replacement to TAVR and surgical aortic valve replacement in the treatment of aortic valve stenosis.

A Novel Hybrid Prosthesis for Open Repair of Acute DeBakey Type I Dissection with Malperfusion: Early Results from the PERSEVERE Trial.

OBJECTIVE: Outcomes after hemiarch repair for acute DeBakey Type I aortic dissection remain unfavorable, with high rates of major adverse events and negative aortic remodeling. The PERSEVERE study evaluates safety and effectiveness of the AMDS Hybrid prosthesis, a novel bare metal stent, in patients presenting with pre-operative malperfusion. METHODS: PERSEVERE is a prospective, single arm, investigational study conducted at 26 sites in the United States. Ninety-three patients underwent acute DeBakey Type I aortic dissection repair with AMDS implantation. The 30-day primary endpoints are composite rate of 4 major adverse events and rate of distal anastomotic new entry tears. The secondary endpoints include aortic remodeling. RESULTS: Clinical malperfusion was documented in 76 patients (82%), with the remaining having only radiographic malperfusion. Median follow-in 93 patients was 5.6 months. Within 30-days, there were 9 deaths (9.7%), 11 patients (11.8%) with new disabling stroke, 18 patients (19.4%) with new onset renal failure requiring ≥ 1 dialysis treatment, and no myocardial infarction. The composite rate of major adverse events (28%) was less than the reference cohort (58%). There were no distal anastomotic new entry tears. Technical success was achieved in 99% of patients. Early remodeling indicated total aortic diameter stability, true lumen expansion, and false lumen reduction in the treated aortic segment. CONCLUSIONS: Early results show significant reduction in major adverse events and distal anastomotic new entry tears, successfully meeting both primary endpoints. The technical success rate was high. AMDS can be used safely in patients with acute DeBakey type I dissection with malperfusion.

Hematocrit and Renal Failure in Aortic Arch Surgery: A Society of Thoracic Surgeons Database Study.

BACKGROUND: We examined the association between cardiopulmonary bypass (CPB) hematocrit and postoperative acute renal failure (ARF) in patients undergoing aortic arch surgery with hypothermic circulatory arrest. METHODS: The Society of Thoracic Surgeons Adult Cardiac Surgery Database was queried from 2011-2019 for patients undergoing aortic arch surgery with hypothermic circulatory arrest. A multivariable logistic regression model estimated the adjusted odds of postoperative ARF based on CPB hematocrit. Effects were stratified by preoperative kidney function and duration of hypothermic circulatory arrest using interaction terms. We also investigated the association between postoperative ARF and major postoperative outcomes using multivariable regression models. RESULTS: On adjusted analysis, higher CPB hematocrit (>20-25%, >25-30%, >30%) was associated with lower odds of ARF as compared to lower CPB hematocrit (≤20%) [>20-25%: aOR=0.78(0.65-0.93), p=0.006, >25-30%: aOR=0.65(0.50-0.84), p=0.0007, >30%: aOR=0.45(0.28-0.72), p=0.0008]. The predicted probability of postoperative ARF by CPB hematocrit was higher in patients with lower preoperative renal function (<60 mL/min/1.73m2) (interaction p=0.03). The association between hematocrit and postoperative ARF was not significantly modified by hypothermic circulatory arrest time (interaction p= 0.74). All postoperative outcomes were significantly worse in patients with postoperative ARF (all p<0.0001). CONCLUSIONS: Among patients undergoing aortic arch surgery, a higher CPB hematocrit level is associated with reduced likelihood of postoperative ARF. Preoperative renal function, but not hypothermic circulatory arrest duration, significantly modified this association. The maintenance of higher CPB hematocrit may reduce the incidence of postoperative ARF, especially for patients with poor preoperative renal function.