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

BACKGROUND: This study 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 to 2019 for patients undergoing aortic arch surgery with hypothermic circulatory arrest. A multivariable logistic regression model estimated the adjusted odds of postoperative ARF on the basis of CPB hematocrit. Effects were stratified by preoperative kidney function and the duration of hypothermic circulatory arrest by using interaction terms. The study also investigated the association between postoperative ARF and major postoperative outcomes by 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 with lower CPB hematocrit (≤20%) (>20-25%, aOR, 0.78; 95% CI, 0.65-0.93; P = .006; >25%-30%, aOR, 0.65; 95% CI, 0.50-0.84; P = .0007; >30%, aOR, 0.45; 95% CI, 0.28-0.72; P = .0008). The predicted probability of postoperative ARF by CPB hematocrit was higher in patients with lower preoperative renal function (estimated glomerular filtration rate, <60 mL/min/1.73 m2) (interaction P = .03). The association between hematocrit and postoperative ARF was not significantly modified by hypothermic circulatory arrest time (interaction P = .74). All postoperative outcomes were significantly worse in patients with postoperative ARF (all P < .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.

Operative Teaching of Coronary Bypass and Need for Repeat Catheterization: Does it Matter Who is Sewing?

OBJECTIVE: There are no studies to date comparing the patency of coronary bypass grafts constructed by attending surgeons versus trainees and the potential consequences of any such disparities. We explored this issue by comparing the patency of individual anastomoses performed by residents versus the attending surgeon. DESIGN: We reviewed 765 continuous cases performed by a single surgeon which involved at least 1 coronary bypass anastomosis, totaling 2,173 distal anastomoses. At a median follow-up time of 36 months (interquartile range 20.5-47.3), 83 (10.9%) patients had undergone 110 cardiac catheterization procedures after their original operation for various indications. This angiographic information provided the data for our comparison cohorts. SETTING: Cardiac surgery practice within an academic setting PARTICIPANTS: Adult patient undergoing coronary bypass grafting RESULTS: Of the 83 patients that underwent repeat catheterization, 23 (27.7%) were resident cases, 25 (30.1%) were attending cases and 35 (42.2%) were mixed. There were 4/83 (4.8%) patients with angiographic evidence of internal mammary artery graft compromise of which 3/4 (75%) had been constructed by the attending surgeon. Angiographic evidence of saphenous vein graft compromise was appreciated in 16/83 (19.3%) patients of which 9/16 (56.3%) of the grafts were constructed by the attending surgeon. CONCLUSIONS: Liberal involvement of surgical trainees as primary operators in coronary revascularization cases led to equivalent rates of postoperative ischemic complications between the attending and resident groups. The outcome equivalence was also maintained when evaluated at the individual anastomosis patency level between the 2 groups. We conclude that academic programs should continue providing trainees significant experience as primary operating surgeons without fear of clinical outcome compromise.

Development of a Novel Society of Thoracic Surgeons Adult Congenital Mortality Risk Model.

BACKGROUND: Operative mortality risk models for adults with congenital heart disease (ACHD) undergoing cardiac operations are essential, given the growing population of these patients, yet they are currently unavailable. Existing adult Society of Thoracic Surgeons (STS) models exclude congenital procedures, whereas existing congenital models exclude operations for acquired disease. We aimed to develop an STS mortality risk model for ACHD patients undergoing cardiac operations. METHODS: Leveraging a comprehensive list of diagnostic and procedure codes, ACHD patients who underwent cardiac operations were identified from the STS Adult Cardiac Surgery Database (versions: v2.73, v2.81, and v2.9) between 2011 and 2019. The model was developed and validated in the ACHD population using a 60/40 development/validation split. Univariate analyses and clinical expertise informed the addition of ACHD-relevant procedure and diagnosis variables to existing STS adult risk model variables. Model performance was assessed overall and in 38 subgroups based on patient demographics, procedures, and diagnoses. RESULTS: Forty-seven procedure and diagnosis variables relevant to ACHD were added to existing STS adult risk model variables. The derived ACHD model for operative mortality was well calibrated within demographic, procedural, and diagnosis subgroups and the overall ACHD population, and discrimination in the validation cohort was excellent (C statistic, 0.815) compared with the model using only existing STS adult risk model variables (C statistic, 0.79; P < .0001). CONCLUSIONS: A novel, high-performing STS ACHD mortality risk model has been developed on the basis of contemporary patient data. The ACHD risk model represents an important expansion of the STS portfolio. Implementation with an online risk calculator is planned.

The utilization of educational resources published by the Thoracic Surgery Residents Association.

Objective: The Thoracic Surgery Residents Association (TSRA) is a trainee-led cardiothoracic surgery organization in North America that has published a multitude of educational resources. However, the utilization of these resources remains unknown. Methods: Surveys were constructed, pilot-tested, and emailed to 527 current cardiothoracic trainees (12 questions) and 780 former trainees who graduated between 2012 and 2019 (16 questions). The surveys assessed the utilization of TSRA educational resources in preparing for clinical practice as well as in-training and American Board of Thoracic Surgery (ABTS) certification examinations. Results: A total of 143 (27%) current trainees and 180 (23%) recent graduates responded. A higher proportion of recent graduates compared with current trainees identified as male (84% vs 66%; P = .001) and graduated from 2- or 3-year traditional training programs (81% vs 41%; P < .001), compared with integrated 6-year (8% vs 49%; P < .001) or 4 + 3 (11% vs 10%; P = .82) pathways. Current trainees most commonly used TSRA resources to prepare for the in-training exam (75%) and operations (73%). Recent graduates most commonly used them to prepare for Oral and/or Written Board Exams (92%) and the in-training exam (89%). Among recent graduates who passed the ABTS Oral Board Exam on the first attempt, 82% (97/118) used TSRA resources to prepare, versus only 48% (25/52) of recent graduates who passed after multiple attempts, failed, have not taken the exam, or preferred not to answer (P < .001). Conclusions: Current cardiothoracic trainees and recent graduates have utilized TSRA educational resources extensively, including to prepare for in-training and ABTS Board examinations.

Beware of an anomalous left circumflex artery when considering aortic valve or root procedures.

Anomalous coronary arteries pose an additional challenge when contemplating surgical options for a patient with aortic valve or root pathology. We demonstrate the course of an anomalous retro-aortic left circumflex coronary artery arising from the right coronary sinus in a patient with an aortic root and ascending aortic aneurysm with severe aortic regurgitation who underwent ascending aorta and aortic valve replacements.

Early Failure of a Bioprosthetic Valve in the Pulmonary Position Causing Panic.

An asymptomatic 26-year-old woman with repaired tetralogy of Fallot and a bioprosthetic pulmonary valve presented with a large thrombosis occluding most of her right ventricular outflow tract and main pulmonary arteries. Our pulmonary embolism response team was emergently consulted, resulting in considerable discussion regarding the treatment modality given the large size and high-risk nature of the thrombosis. Ultimately, she was started on a heparin infusion until she could undergo open thrombectomy and pulmonary valve repeat replacement. The patient's asymptomatic presentation, despite the considerable clot burden, complicated our approach to management but ultimately led to a measured and timely intervention.

The Society of Thoracic Surgeons Coronary Artery Bypass Graft Composite Measure: 2021 Methodology Update.

BACKGROUND: The Society of Thoracic Surgeons (STS) original coronary artery bypass graft surgery (CABG) composite measure uses a 1-year analytic cohort and 98% credible intervals (CrI) to classify better than expected (3-star) performance or worse than expected (1-star) performance. As CABG volumes per STS participant (eg, hospital or practice group) have decreased, it has become more challenging to classify performance categories using this approach, especially for lower volume programs, and alternative approaches have been explored. METHODS: Among 990 STS Adult Cardiac Surgery Database participants, performance classifications for the CABG composite were studied using various analytic cohorts: 1 year (current approach, 2017); 3 years (2015 to 2017); last 450 cases within 3 years; and most recent year (2017) plus additional cases to 450 total. We also compared 98% CrI with 95% CrI (used in other STS composite measures). RESULTS: Using 3 years of data and 95% CrIs, 113 of 990 participants (11.4%) were classified 1-star and 198 (20%) 3-star. Compared with 1-year analytic cohorts and 98% CrI, the absolute and relative increases in the proportion of 3-star participants were 14 percentage points and 233% (n = 198 [20%] vs n = 59 [6%]). Corresponding changes for 1-star participants were 6.5 percentage points and 133% (n = 113 [11.4%] vs n = 48 [4.9%]). These changes were particularly notable among lower volume (fewer than 199 CABG per year) participants. Measure reliability with the 3-year, 95% CrI modification is 0.78. CONCLUSIONS: Compared with current STS CABG composite methodology, a 3-year analytic cohort and 95% CrI increases the number and proportion of better or worse than expected outliers, especially among lower-volume Adult Cardiac Surgery Database participants. This revised methodology is also now consistent with other STS procedure composites.

Current Penetration, Completeness, and Representativeness of The Society of Thoracic Surgeons Adult Cardiac Surgery Database.

BACKGROUND: The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD) is the largest cardiac surgical database in the world. Linked data from STS ACSD and the Centers for Medicare and Medicaid Services (CMS) database were used to determine contemporary completeness, penetration, and representativeness of STS ACSD. METHODS: Variables common to both STS and CMS databases were used to link STS procedures to CMS data for all CMS coronary artery bypass grafting surgery (CABG) discharges between 2000 and 2018, inclusive. For each CMS CABG hospitalization, it was determined whether a matching STS record existed. RESULTS: Center-level penetration (number of CMS sites with at least 1 matched STS participant divided by total number of CMS CABG sites) increased from 45% in 2000 to 95% in 2018. In 2018, 949 of 1004 CMS CABG sites (95%) were linked to an STS site. Patient-level penetration (number of CMS CABG hospitalizations at STS sites divided by total number of CMS CABG hospitalizations) increased from 51% in 2000 to 97% in 2018. In 2018, 68,584 of 70,818 CMS CABG hospitalizations (97%) occurred at an STS site. Completeness of case inclusion at STS sites (number of CMS CABG cases at STS sites linked to STS records divided by total number of CMS CABG cases at STS sites) increased from 88% in 2000 to 98% in 2018. In 2018, 66,673 of 68,108 CMS CABG hospitalizations at STS sites (98%) were linked to an STS record. CONCLUSIONS: Linkage of the STS and CMS databases demonstrates high and increasing penetration and completeness of STS ACSD. STS ACSD now includes 97% of CABG in the United States.

Revisiting performance metrics for prediction with rare outcomes.

Machine learning algorithms are increasingly used in the clinical literature, claiming advantages over logistic regression. However, they are generally designed to maximize the area under the receiver operating characteristic curve. While area under the receiver operating characteristic curve and other measures of accuracy are commonly reported for evaluating binary prediction problems, these metrics can be misleading. We aim to give clinical and machine learning researchers a realistic medical example of the dangers of relying on a single measure of discriminatory performance to evaluate binary prediction questions. Prediction of medical complications after surgery is a frequent but challenging task because many post-surgery outcomes are rare. We predicted post-surgery mortality among patients in a clinical registry who received at least one aortic valve replacement. Estimation incorporated multiple evaluation metrics and algorithms typically regarded as performing well with rare outcomes, as well as an ensemble and a new extension of the lasso for multiple unordered treatments. Results demonstrated high accuracy for all algorithms with moderate measures of cross-validated area under the receiver operating characteristic curve. False positive rates were <1%, however, true positive rates were <7%, even when paired with a 100% positive predictive value, and graphical representations of calibration were poor. Similar results were seen in simulations, with the addition of high area under the receiver operating characteristic curve (>90%) accompanying low true positive rates. Clinical studies should not primarily report only area under the receiver operating characteristic curve or accuracy.

The Resident-Run Minor Surgery Clinic: A Four-Year Analysis of Patient Outcomes, Satisfaction, and Resident Education.

OBJECTIVE: A resident-run minor surgery clinic was developed to increase resident procedural autonomy. We evaluated whether 1) there was a significant difference between complications and patient satisfaction when procedures were independently performed by surgical residents vs. a surgical attending and 2) if participation was associated with an increase in resident procedural confidence. DESIGN: Third year general surgery residents participated in a weekly procedure clinic from 2014-2018. Post-procedure complications and patient satisfaction were compared between patients operated on by residents vs. the staff surgeon. Residents were surveyed regarding their confidence in independently performing a variety of clinic-based patient care tasks. SETTING: Massachusetts General Hospital General in Boston, MA; an academic tertiary care general surgery residency program. PARTICIPANTS: Post-graduate year three general surgery residents that ran the clinic as part of a general surgery rotation. RESULTS: 1230 patients underwent 1592 procedures (612 in resident clinic, 980 in attending clinic). There was no significant difference in the 30-day complication rate between patients operated on by the resident vs. attending (2.5% vs. 1.9%, p = 0.49). 459 patient satisfaction surveys were administered with a 79.1% response rate. There was no significant difference in the overall quality of care rating between residents and the attending surgeon (87.5% top-box rating vs. 93.1%, p = 0.15). Twenty-one residents completed both a pre- and post-rotation survey (77.8% response rate). The proportion of residents indicating that they could independently perform a variety of patient care tasks significantly increased across the rotation (all p < 0.05). CONCLUSION: Mid-level general surgery residents can independently perform office-based procedures without detriment to safety or patient satisfaction. The resident-run procedure clinic serves as an environment for residents to grow in confidence in both technical and non-technical skills. Given the high rate at which patients provide resident feedback, future work may investigate how to best incorporate patient derived evaluations into resident assessment.

Outcomes of open and endovascular repair of Kommerell diverticulum.

OBJECTIVES: Kommerell diverticulum (KD) is a rare congenital vascular anomaly often associated with an aberrant subclavian artery (ASCA). Definitive indications for intervention remain unclear. We present open and endovascular (EV) operative outcomes in a large contemporary series and propose a management algorithm. METHODS: Between 2004 and 2020, 224 patients presented with ASCA and associated KD to our institution. Of the 43 (19.2%) patients who underwent operative repair, 31 (72.1%) had open surgical (OS) repair via thoracotomy and 12 (27.9%) had EV repair. Univariable and bivariable statistical analyses were conducted stratified by approach. The median follow-up time was 5.4 years (IQR, 2.9-9.7). RESULTS: Patients in EV group were older (68 years vs 47 years, P < 0.001) and had larger aneurysms (base diameter 3.2 cm vs 21.5 cm, P = 0.007). All patients with dysphagia lusoria were treated with open surgery (n = 20). Asymptomatic patients with incidentally detected KD (50% vs 16.1%), those with chest or back pain (50% vs 19.4%) and patients who presented with an aortic emergency (25% vs 6.5%) were more likely to be treated endovascularly (P = 0.001). Carotid-to-subclavian bypass was used in 38 (88.4%) patients. There were no operative mortalities. In-hospital mortality was similar between groups (3.2% vs 16.7%, P = 0.121). Mid-term mortality was higher in the EV group [4 (33.8%) vs 0, P < 0.001]. There were 2 (15.4%) postoperative strokes in the EV group. There were no statistically significant differences in other postoperative complications or hospital length of stay between groups. CONCLUSIONS: KD can be managed using open or EV approaches with low morbidity and mortality. Treatment strategy should depend on clinical presentation and patient factors.

Impact of staff turnover during cardiac surgical procedures.

OBJECTIVE: The impact of staff turnover during cardiac procedures is unknown. Accurate inventory of sharps (needles/blades) requires attention by surgical teams, and sharp count errors result in delays, can lead to retained foreign objects, and may signify communication breakdown. We hypothesized that increased team turnover raises the likelihood of sharp count errors and may negatively affect patient outcomes. METHODS: All cardiac operations performed at our institution from May 2011 to March 2016 were reviewed for sharp count errors from a prospectively maintained database. Univariate and multivariable analyses were performed. RESULTS: Among 7264 consecutive cardiac operations, sharp count errors occurred in 723 cases (10%). There were no retained sharps detected by x-ray in our series. Sharp count errors were lower on first start cases (7.7% vs 10.7%, P < .001). Cases with sharp count errors were longer than those without (7 vs 5.7 hours, P < .001). In multivariable analysis, factors associated with an increase in sharp count errors were non-first start cases (odds ratio [OR], 1.3; P = .006), weekend cases (OR, 1.6; P < .004), more than 2 scrub personnel (3 scrubs: OR, 1.3; P = .032; 4 scrubs: OR, 2; P < .001; 5 scrubs: OR, 2.4; P = .004), and more than 1 circulating nurse (2 nurses: OR, 1.9; P < .001; 3 nurses: OR, 2; P < .001; 4 nurses: OR, 2.4; P < .001; 5 nurses: OR, 3.1; P < .001). Sharp count errors were associated with higher rates of in-hospital mortality (OR, 1.9; P = .038). CONCLUSIONS: Sharp count errors are more prevalent with increased team turnover and during non-first start cases or weekends. Sharp count errors may be a surrogate marker for other errors and thus increased mortality. Reducing intraoperative team turnover or optimizing hand-offs may reduce sharp count errors.