Blending three repair techniques in a case of complex mitral valve endocarditis

In a 39-year-old male with mitral valve endocarditis, after 6 weeks of intravenous antibiotics, echocardiography confirmed multiple vegetations on both leaflets, a flail posterior leaflet flail and contained perforation of the anterior leaflet in a windsock-like morphology. All vegetations, diseased and ruptured chords and the windsock-like contained rupture of the anterior leaflet were carefully resected via a right minithoracotomy and with femoral cannulation. Three repair techniques were blended to reconstruct the valve: (1) A large, infected portion of the prolapsing posterior leaflet was resected in a triangular fashion, and the edges were re-approximated using continuous 5-0 polypropylene sutures. (2) The anterior leaflet defect was repaired with a circular autologous pericardial patch that had been soaked in glutaraldehyde. (3) A set of artificial chords for P2 was created using CV-4 polytetrafluoroethylene sutures and adjusted under repeated saline inflation. A 38-mm Edwards Physio-I annuloplasty ring was implanted. The artificial chords were adjusted again after annuloplasty and then tied. Transoesophageal echocardiography (TEE) confirmed the absence of residual mitral regurgitation and systolic anterior motion and a mean pressure gradient of 3 mmHg. The patient was discharged after 5 days with a peripherally inserted central catheter to complete an additional 4 weeks of intravenous antibiotics and had an uneventful recovery.

Neochordal Goldilocks: Analyzing the biomechanics of neochord length on papillary muscle forces suggests higher tolerance to shorter neochordae

OBJECTIVE

Estimating neochord lengths during mitral valve repair is challenging, because approximation must be performed largely based on intuition and surgical experience. Little data exist on quantifying the effects of neochord length misestimation. We aimed to evaluate the impact of neochord length on papillary muscle forces and mitral valve hemodynamics, which is especially pertinent because increased forces have been linked to aberrant mitral valve biomechanics.

METHODS

Porcine mitral valves (n = 8) were mounted in an ex vivo heart simulator, and papillary muscles were fixed to high-resolution strain gauges while hemodynamic data were recorded. We used an adjustable system to modulate neochord lengths. Optimal length was qualitatively verified by a single experienced operator, and neochordae were randomly lengthened or shortened in 1-mm increments up to ±5 mm from the optimal length.

RESULTS

Optimal length neochordae resulted in the lowest peak composite papillary muscle forces (6.94 ± 0.29 N), significantly different from all lengths greater than ±1 mm. Both longer and shorter neochordae increased forces linearly according to difference from optimal length. Both peak papillary muscle forces and mitral regurgitation scaled more aggressively for longer versus shorter neochordae by factors of 1.6 and 6.9, respectively.

CONCLUSIONS

Leveraging precision ex vivo heart simulation, we found that millimeter-level neochord length differences can result in significant differences in papillary muscle forces and mitral regurgitation, thereby altering valvular biomechanics. Differences in lengthened versus shortened neochordae scaling of forces and mitral regurgitation may indicate different levels of biomechanical tolerance toward longer and shorter neochordae. Our findings highlight the need for more thorough biomechanical understanding of neochordal mitral valve repair.

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.

Recruited macrophages elicit atrial fibrillation

Atrial fibrillation disrupts contraction of the atria, leading to stroke and heart failure. We deciphered how immune and stromal cells contribute to atrial fibrillation. Single-cell transcriptomes from human atria documented inflammatory monocyte and SPP1+ macrophage expansion in atrial fibrillation. Combining hypertension, obesity, and mitral valve regurgitation (HOMER) in mice elicited enlarged, fibrosed, and fibrillation-prone atria. Single-cell transcriptomes from HOMER mouse atria recapitulated cell composition and transcriptome changes observed in patients. Inhibiting monocyte migration reduced arrhythmia in Ccr2-∕- HOMER mice. Cell-cell interaction analysis identified SPP1 as a pleiotropic signal that promotes atrial fibrillation through cross-talk with local immune and stromal cells. Deleting Spp1 reduced atrial fibrillation in HOMER mice. These results identify SPP1+ macrophages as targets for immunotherapy in atrial fibrillation.

Utilization of Engineering Advances for Detailed Biomechanical Characterization of the Mitral-Ventricular Relationship to Optimize Repair Strategies: A Comprehensive Review

The geometrical details and biomechanical relationships of the mitral valve-left ventricular apparatus are very complex and have posed as an area of research interest for decades. These characteristics play a major role in identifying and perfecting the optimal approaches to treat diseases of this system when the restoration of biomechanical and mechano-biological conditions becomes the main target. Over the years, engineering approaches have helped to revolutionize the field in this regard. Furthermore, advanced modelling modalities have contributed greatly to the development of novel devices and less invasive strategies. This article provides an overview and narrative of the evolution of mitral valve therapy with special focus on two diseases frequently encountered by cardiac surgeons and interventional cardiologists: ischemic and degenerative mitral regurgitation.

Abnormal Mechanics Relate to Myocardial Fibrosis and Ventricular Arrhythmias in Patients With Mitral Valve Prolapse

BACKGROUND

The relation between ventricular arrhythmia and fibrosis in mitral valve prolapse (MVP) is reported, but underlying valve-induced mechanisms remain unknown. We evaluated the association between abnormal MVP-related mechanics and myocardial fibrosis, and their association with arrhythmia.

METHODS

We studied 113 patients with MVP with both echocardiogram and gadolinium cardiac magnetic resonance imaging for myocardial fibrosis. Two-dimensional and speckle-tracking echocardiography evaluated mitral regurgitation, superior leaflet and papillary muscle displacement with associated exaggerated basal myocardial systolic curling, and myocardial longitudinal strain. Follow-up assessed arrhythmic events (nonsustained or sustained ventricular tachycardia or ventricular fibrillation).

RESULTS

Myocardial fibrosis was observed in 43 patients with MVP, predominantly in the basal-midventricular inferior-lateral wall and papillary muscles. Patients with MVP with fibrosis had greater mitral regurgitation, prolapse, and superior papillary muscle displacement with basal curling and more impaired inferior-posterior basal strain than those without fibrosis (P<0.001). An abnormal strain pattern with distinct peaks pre-end-systole and post-end-systole in inferior-lateral wall was frequent in patients with fibrosis (81 versus 26%, P<0.001) but absent in patients without MVP with basal inferior-lateral wall fibrosis (n=20). During median follow-up of 1008 days, 36 of 87 patients with MVP with >6-month follow-up developed ventricular arrhythmias associated (univariable) with fibrosis, greater prolapse, mitral annular disjunction, and double-peak strain. In multivariable analysis, double-peak strain showed incremental risk of arrhythmia over fibrosis.

CONCLUSIONS

Basal inferior-posterior myocardial fibrosis in MVP is associated with abnormal MVP-related myocardial mechanics, which are potentially associated with ventricular arrhythmia. These associations suggest pathophysiological links between MVP-related mechanical abnormalities and myocardial fibrosis, which also may relate to ventricular arrhythmia and offer potential imaging markers of increased arrhythmic risk.

Left Atrial Function and Not Volume Predicts Mid-to-Late Atrial Fibrillation after Mitral Valve Repair

OBJECTIVES

Patients undergoing surgical mitral valve repair for degenerative mitral regurgitation are at risk of even late postoperative atrial fibrillation (AF). Left atrial (LA) functionhas been shown superior to LA volume in evaluating risk of AF in diverse cardiac conditions. We therefore investigated the prognostic value of LA function and volume in predicting mid-to-late postoperative AF after mitral valve repair (>30 days postoperatively).

METHODS

We retrospectively identified all patients who underwent mitral valve repair for degenerative mitral regurgitation between 2012-2019 at our institution. Exclusion criteria were preoperative AF, concomitant procedures, re-operations, missing or insufficiently processable preoperative echocardiograms, and missing follow-up. LA function and volume measurements were conducted using speckle-tracking strain echocardiographic analysis. Postoperative LA function was measured in a subgroup with sufficient postoperative echocardiograms.

RESULTS

We included 251 patients, of which 39 (15.5%) experienced AF in the mid-to-late postoperative period. Reduced LA strain parameters and more than mild preoperative tricuspid regurgitation were independently associated with mid-to-late postoperative AF. LA volume index had no association with mid-to-late postoperative AF in univariable analysis and did not improve performance of multivariable models. Patients with mid-to-late AF exhibited diminished improvement in LA function after surgery.

CONCLUSION

In mitral valve repair patients, LA function (but not volume) showed independent predictive value for mid-to-late postoperative AF. Including left atrial function into surgical decision making and approach may identify patients who will benefit from earlier intervention with the aim to prevent irreversible left atrial damage with consequent risk of postoperative AF.

Histopathological insights into mitral valve prolapse-induced fibrosis

Mitral valve prolapse (MVP) is a cardiac valve disease that not only affects the mitral valve (MV), provoking mitral regurgitation, but also leads to maladaptive structural changes in the heart. Such structural changes include the formation of left ventricular (LV) regionalized fibrosis, especially affecting the papillary muscles and inferobasal LV wall. The occurrence of regional fibrosis in MVP patients is hypothesized to be a consequence of increased mechanical stress on the papillary muscles and surrounding myocardium during systole and altered mitral annular motion. These mechanisms appear to induce fibrosis in valve-linked regions, independent of volume-overload remodeling effects of mitral regurgitation. In clinical practice, quantification of myocardial fibrosis is performed with cardiovascular magnetic resonance (CMR) imaging, even though CMR has sensitivity limitations in detecting myocardial fibrosis, especially in detecting interstitial fibrosis. Regional LV fibrosis is clinically relevant because even in the absence of mitral regurgitation, it has been associated with ventricular arrhythmias and sudden cardiac death in MVP patients. Myocardial fibrosis may also be associated with LV dysfunction following MV surgery. The current article provides an overview of current histopathological studies investigating LV fibrosis and remodeling in MVP patients. In addition, we elucidate the ability of histopathological studies to quantify fibrotic remodeling in MVP and gain deeper understanding of the pathophysiological processes. Furthermore, molecular changes such as alterations in collagen expression in MVP patients are reviewed.

Building a successful minimally invasive mitral valve repair program before introducing the robotic approach: The Massachusetts General Hospital experience

Background

Patients with mitral valve prolapse (MVP) requiring surgical repair (MVr) are increasingly operated using minimally invasive strategies. Skill acquisition may be facilitated by a dedicated MVr program. We present here our institutional experience in establishing minimally invasive MVr (starting in 2014), laying the foundation to introduce robotic MVr.

Methods

We reviewed all patients that had undergone MVr for MVP via sternotomy or mini-thoracotomy between January 2013 and December 2020 at our institution. In addition, all cases of robotic MVr between January 2021 and August 2022 were analyzed. Case complexity, repair techniques, and outcomes are presented for the conventional sternotomy, right mini-thoracotomy and robotic approaches. A subgroup analysis comparing only isolated MVr cases via sternotomy vs. right mini-thoracotomy was conducted using propensity score matching.

Results

Between 2013 and 2020, 799 patients were operated for native MVP at our institution, of which 761 (95.2%) received planned MVr (263 [34.6%] via mini-thoracotomy) and 38 (4.8%) received planned MV replacement. With increasing proportions of minimally invasive procedures (2014: 14.8%, 2020: 46.5%), we observed a continuous growth in overall institutional volume of MVP (n = 69 in 2013; n = 127 in 2020) and markedly improved institutional rates of successful MVr, with 95.4% in 2013 vs. 99.2% in 2020. Over this period, a higher complexity of cases were treated minimally-invasively and increased use of neochord implantation ± limited leaflet resection was observed. Patients operated minimally invasively had longer aortic cross-clamp times (94 vs. 88 min, p = 0.001) but shorter ventilation times (4.4 vs. 4.8 h, p = 0.002) and hospital stays (5 vs. 6 days, p < 0.001) than those operated via sternotomy, with no significant differences in other outcome variables. A total of 16 patients underwent robotically assisted MVr with successful repair in all cases.

Conclusion

A focused approach towards minimally invasive MVr has transformed the overall MVr strategy (incision; repair techniques) at our institution, leading to a growth in MVr volume and improved repair rates without significant complications. On this foundation, robotic MVr was first introduced at our institution in 2021 with excellent outcomes. This emphasizes the importance of building a competent team to perform these challenging operations, especially during the initial learning curve.

Native and Post-Repair Residual Mitral Valve Prolapse Increases Forces Exerted on the Papillary Muscles: A Possible Mechanism for Localized Fibrosis?

BACKGROUND

Recent studies have linked mitral valve prolapse to localized myocardial fibrosis, ventricular arrhythmia, and even sudden cardiac death independent of mitral regurgitation or hemodynamic dysfunction. The primary mechanistic theory is rooted in increased papillary muscle traction and forces due to prolapse, yet no biomechanical evidence exists showing increased forces. Our objective was to evaluate the biomechanical relationship between prolapse and papillary muscle forces, leveraging advances in ex vivo modeling and technologies. We hypothesized that mitral valve prolapse with limited hemodynamic dysfunction leads to significantly higher papillary muscle forces, which could be a possible trigger for cellular and electrophysiological changes in the papillary muscles and adjacent myocardium.

METHODS

We developed an ex vivo papillary muscle force transduction and novel neochord length adjustment system capable of modeling targeted prolapse. Using 3 unique ovine models of mitral valve prolapse (bileaflet or posterior leaflet prolapse), we directly measured hemodynamics and forces, comparing physiologic and prolapsing valves.

RESULTS

We found that bileaflet prolapse significantly increases papillary muscle forces by 5% to 15% compared with an optimally coapting valve, which are correlated with statistically significant decreases in coaptation length. Moreover, we observed significant changes in the force profiles for prolapsing valves when compared with normal controls.

CONCLUSIONS

We discovered that bileaflet prolapse with the absence of hemodynamic dysfunction results in significantly elevated forces and altered dynamics on the papillary muscles. Our work suggests that the sole reduction of mitral regurgitation without addressing reduced coaptation lengths and thus increased leaflet surface area exposed to ventricular pressure gradients (ie, billowing leaflets) is insufficient for an optimal repair.

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.

Association between hospital cardiovascular procedural volumes and transcatheter mitral valve repair outcomes

BACKGROUND

Cardiovascular procedural volumes can serve as metrics of hospital infrastructure and quality, and are the basis for thresholds for initiating transcatheter mitral valve repair (TMVr) programs. Whether hospital volumes of TMVr, surgical mitral valve replacement or repair (SMVRr), and percutaneous coronary intervention (PCI) are indicators of TMVr quality of care is not known.

METHODS

We used the 2017 Nationwide Readmissions Database to identify hospitals that performed at least 5 TMVr procedures. Hospitals were divided into quartiles of TMVr volume. Associations of hospital TMVr, SMVRr, and PCI volumes, as well as SMVRr and PCI outcomes with TMVr outcomes were examined. Outcomes studied were risk-standardized in-hospital mortality rate (RSMR) and 30-day readmission rate (RSRR).

RESULTS

The study included 3404 TMVr procedures performed across 150 hospitals in the US. The median hospital TMVr volume was 17 (IQR 10, 28). The mean hospital-level RSMR and RSRR for TMVr were 3.0% (95% CI 2.5%, 3.4%) and 14.8% (95% CI 14.5%, 15.0%), respectively. There was no significant association between hospital TMVr volume (as quartiles or as a continuous variable) and TMVr RSMR or RSRR (P > 0.05). Similarly, there was weak or no correlation between hospital SMVRr and PCI volumes and outcomes with TMVr RSMR or RSRR (Pearson correlation coefficients, r = -0.199 to 0.269).

CONCLUSION

In this study, we found no relationship between hospital TMVr, SMVRr, and PCI volume and TMVr outcomes. Further studies are needed to determine more appropriate structure and process measures to assess the performance of established and new TMVr centers.

Association of Pulmonary Hypertension With Clinical Outcomes of Transcatheter Mitral Valve Repair

Importance

Pulmonary hypertension (pHTN) is associated with increased risk of mortality after mitral valve surgery for mitral regurgitation. However, its association with clinical outcomes in patients undergoing transcatheter mitral valve repair (TMVr) with a commercially available system (MitraClip) is unknown.

Objective

To assess the association of pHTN with readmissions for heart failure and 1-year all-cause mortality after TMVr.

Design, Setting, and Participants

This retrospective cohort study analyzed 4071 patients who underwent TMVr with the MitraClip system from November 4, 2013, through March 31, 2017, across 232 US sites in the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy registry. Patients were stratified into the following 4 groups based on invasive mean pulmonary arterial pressure (mPAP): 1103 with no pHTN (mPAP, <25 mm Hg [group 1]); 1399 with mild pHTN (mPAP, 25-34 mm Hg [group 2]); 1011 with moderate pHTN (mPAP, 35-44 mm Hg [group 3]); and 558 with severe pHTN (mPAP, ≥45 mm Hg [group 4]). Data were analyzed from November 4, 2013, through March 31, 2017.

Interventions

Patients were stratified into groups before TMVr, and clinical outcomes were assessed at 1 year after intervention.

Main Outcomes and Measures

Primary end point was a composite of 1-year mortality and readmissions for heart failure. Secondary end points were 30-day and 1-year mortality and readmissions for heart failure. Linkage to Centers for Medicare & Medicaid Services administrative claims was performed to assess 1-year outcomes in 2381 patients.

Results

Among the 4071 patients included in the analysis, the median age was 81 years (interquartile range, 73-86 years); 1885 (46.3%) were women and 2186 (53.7%) were men. The composite rate of 1-year mortality and readmissions for heart failure was 33.6% (95% CI, 31.6%-35.7%), which was higher in those with pHTN (27.8% [95% CI, 24.2%-31.5%] in group 1, 32.4% [95% CI, 29.0%-35.8%] in group 2, 36.0% [95% CI, 31.8%-40.2%] in group 3, and 45.2% [95% CI, 39.1%-51.0%] in group 4; P < .001). Similarly, 1-year mortality (16.3% [95% CI, 13.4%-19.5%] in group 1, 19.8% [95% CI, 17.0%-22.8%] in group 2, 22.4% [95% CI, 18.8%-26.1%] in group 3, and 27.8% [95% CI, 22.6%-33.3%] in group 4; P < .001) increased across pHTN groups. The association of pHTN with mortality persisted despite multivariable adjustment (hazard ratio per 5-mm Hg mPAP increase, 1.05; 95% CI, 1.01-1.09; P = .02).

Conclusions and Relevance

These findings suggest that pHTN is associated with increased mortality and readmission for heart failure in patients undergoing TMVr using the MitraClip system for severe mitral regurgitation. Further efforts are needed to determine whether earlier intervention before pHTN develops will improve clinical outcomes.

Factors Related to Survival in Low-Glomerular Filtration Rate Cohorts Undergoing Lung Transplant

BACKGROUND

Historically, a glomerular filtration rate (GFR) of less than 50 mL/min per 1.73 m² has been considered a contraindication to lung transplantation. Combined or sequential lung-kidney transplantation is an option for those with a GFR less than 30 mL/min per 1.73 m². Patients with a GFR of 30 to 50 mL/min per 1.73 m² are provided with no options for transplantation. This study explores factors associated with improved survival in patients who undergo isolated lung transplantation with a GFR of 30 to 50 mL/min per 1.73 m².

METHODS

The United Network for Organ Sharing database was queried for adult patients undergoing primary isolated lung transplantation between January 2007 and March 2018. Regression models were used to identify factors associated with improved survival in lung recipients with a preoperative GFR of 30 to 50 mL/min per 1.73 m². The propensity score method was used to match highly performing patients (outpatient recipients aged less than 60 years) with a GFR of 30 to 50 mL/min per 1.73 m² with patients who had a GFR greater than 50 mL/min per 1.73 m². Kaplan-Meier, Cox, and logistic regression analyses compared outcomes in matched populations.

RESULTS

A total of 21,282 lung transplantations were performed during the study period. Compared with patients with a GFR greater than 50 mL/min per 1.73 m², survival was significantly worse for patients with a GFR of 30 to 50 mL/min per 1.73 m². Multivariate analysis of patients with a GFR of 30 to 50 mL/min per 1.73 m² demonstrated outpatient status and age less than 60 years to be predictive of superior survival. After propensity matching, survival of this highly performing subset with a GFR of 30 to 50 mL/min per 1.73 m² was no different from that of patients with a normal GFR.

CONCLUSIONS

Outpatient recipients aged less than 60 years represent an optimal subset of patients with a GFR of 30 to 50 mL/min per 1.73 m². Lung transplant listing should not be declined based only on a GFR less than 50 mL/min per 1.73 m².

Pulmonary Venoatrial Connection Using a Ringed Tube Graft to Repair Partial Anomalous Pulmonary Venous Return

Left-sided partial anomalous pulmonary venous return (left pulmonary veins to left vertical vein) was repaired in a 70-year-old patient by ligation of the vertical vein and connection of the pulmonary veins to the left atrial appendage using a ringed polytetrafluoroethylene tube graft. The graft made the connection technically easier and facilitated a torque-free and tension-free anastomosis that was "stented" open by the rings.

Intra-aortic balloon pump placement in coronary artery bypass grafting patients by day of admission

INTRODUCTION

Intra-Aortic Balloon Pumps (IABPs) can be utilized to provide hemodynamic support in high risk patients awaiting coronary artery bypass grafting (CABG). There are many indications for IABP and institutional practice patterns regarding the placement of IABPs is variable. As a result, the preoperative placement of an IABP in a patient awaiting CABG is not standardized and may vary according to non-clinical factors. We hypothesize that the rate of IABP placement varies by day of the week.

METHODS

A retrospective cohort analysis of the Office of Statewide Health Planning and Development database from 2006 to 2010 was performed. All patients admitted for CABG were included. Patients who died within 24 h of admission and those who had absolute contraindications to IABP placement were excluded. The primary outcome was preoperative IABP placement versus non-placement. A multivariable logistic regression analysis to identify predictors of IABP placement was performed, adjusting for patient demographics, clinical factors, and system variables.

RESULTS

A total of 46,347 patients underwent CABG, of which 7695 (16.60%) had an IABP placed preoperatively. On unadjusted analysis, IABP rates were significantly higher on weekends versus weekdays (20.83% vs. 15.70%, p < 0.001). On adjusted analysis, patients awaiting CABG were 1.30 times more likely to have an IABP placed on weekends than on weekdays (OR: 1.30, 95% CI 1.20-1.40, p < 0.001).

CONCLUSION

The odds of preoperative IABP placement prior to CABG is significantly increased on weekends compared to weekdays, even when controlling for clinical factors. Further exploration of this phenomenon and its associations are warranted.

Preoperative penicillin allergy testing in patients undergoing cardiac surgery

BACKGROUND

Cefazolin is a first-line prophylactic antibiotic used to prevent surgical site infections (SSIs) in cardiac surgery. Patients with a history of penicillin allergy often receive less effective second-line antibiotics, which is associated with an increased SSI risk.

OBJECTIVE

To describe the impact of preoperative penicillin allergy evaluation on perioperative cefazolin use in patients undergoing cardiac surgery.

METHODS

We performed a retrospective cohort study of patients with a documented penicillin allergy who underwent cardiac surgery at the Massachusetts General Hospital from September 2015 to December 2018. We describe penicillin allergy evaluation assessment and outcomes. We evaluated the association between preoperative penicillin allergy evaluation and first-line perioperative antibiotic use using a multivariable logistic regression model.

RESULTS

Of 3802 cardiac surgical patients, 510 (13%) had a documented penicillin allergy; 165 (33%) were referred to allergy and immunology practitioners. Of 160 patients (31%) who underwent penicillin allergy evaluation (ie, penicillin skin testing and, if results were negative, an amoxicillin challenge), 154 (97%) were found not to have a penicillin allergy. Patients who underwent preoperative penicillin allergy evaluation were more likely to receive the first-line perioperative antibiotic (92% vs 38%, P < .001). After adjusting for potential confounders, patients who underwent preoperative penicillin allergy evaluation had higher odds of first-line perioperative antibiotic use (adjusted odds ratio, 26.6; 95% CI, 12.8-55.2).

CONCLUSION

Integrating penicillin allergy evaluation into routine preoperative care ensured that almost all evaluated patients undergoing cardiac surgery received first-line antibiotic prophylaxis, a critical component of SSI risk reduction. Further efforts are needed to increase access to preoperative allergy evaluation.

Increasing donor sequence number is not associated with inferior outcomes in lung transplantation

BACKGROUND

Donor sequence number (DSN) represents the number of recipients to whom an organ has been offered. The impact of seeing numerous prior refusals may potentially influence the decision to accept an organ. We sought to determine if DSN was associated with inferior posttransplant outcomes.

METHODS

Using the United Network for Organ Sharing database, a retrospective analysis was performed on 22 361 patients who received a lung transplant between 2005 and 2017. Patients were grouped into low DSN (1-24, n = 16 860) and high DSN (>24, n = 5501) categories. Baseline characteristics and posttransplant outcomes were analyzed. An institutional subgroup was also analyzed to compare rates of primary graft dysfunction (PGD) posttransplant.

RESULTS

The DSN ranged from 1 to 1735 (median, 7; interquartile range, 2-24). A total of 18 507 recipients received an organ with at least one prior refusal. Recipients of donors with a higher DSN were older (58 vs 55 years; P < .01) but had lower lung allocation scores (43.5 vs 47.5; P < .01). On adjusted analysis, high DSN was not associated with increased mortality (hazard ratio, 0.99; 95% confidence interval, 0.94-1.04; P = .77). There was no difference in the incidence of graft failure (P = .37) or retransplantation (P = .24). Recipient subgroups who received donors with an increasing DSN >50 and >75 also demonstrated no difference in mortality when compared with a low DSN (P = .86 and P = .97). There was no difference in PGD for patients with a low vs a high DSN at any time posttransplant.

CONCLUSIONS

DSN is not associated with increased mortality in patients undergoing lung transplantation and should not negatively influence the decision to accept a lung for transplant.

Open Atrial Transcatheter Mitral Valve Replacement in Patients With Mitral Annular Calcification

BACKGROUND

Mitral valve replacement in the setting of severe mitral annular calcification remains a surgical challenge. Transcatheter mitral valve replacement (TMVR) using an aortic balloon-expandable transcatheter heart valve is emerging as a potential treatment option for high surgical risk patients. Transseptal, transapical, or transatrial access is not always feasible, so an understanding of alternative implantation techniques is important.

OBJECTIVES

The authors sought to present a step-by-step description of a contemporary transatrial TMVR technique using balloon-expandable aortic transcatheter heart valves. This procedure has evolved over time to address valve migration, left ventricular outflow tract obstruction, and paravalvular leak. The authors present a refined technique that has been associated with the most reproducible outcomes.

METHODS

A step-by-step description of the TMVR technique and outcomes of 8 patients treated using this technique are described. Baseline patient clinical and echocardiographic characteristics and 30-day post-TMVR outcomes are presented.

RESULTS

Eight patients underwent transatrial TMVR at a single institution. Five had previous cardiac surgery. Mean STS score was 8%. Technical success by MVARC (Mitral Valve Academic Research Consortium) criteria was 100%. There was zero in-hospital and 30-day mortality. Procedural success by MVARC criteria at 30 days was 100%. Paravalvular leak immediately post-implant was none or trace in 6 and mild in 1.

CONCLUSIONS

The technique described is reproducible and was associated with favorable outcomes in this early experience. It represents a useful technique for the treatment of mitral valve disease in the setting of severe annular calcification. A structured and defined implantation technique is critical to investigators as this field evolves.

Failure to Rescue Contributes to Center-Level Differences in Mortality After Lung Transplantation

BACKGROUND

The clinical response to postoperative complications after lung transplantation (LTx) may contribute to mortality differences among transplantation centers. The ability to avoid mortality after a complication-failure to rescue (FTR)-may be an effective quality metric in LTx.

METHODS

The United Network for Organ Sharing database was queried for adult, first-time, lung-only transplantations from May 2005 to December 2015. Transplantation centers were stratified into equal-sized terciles on the basis of observed operative mortality rates. Several postoperative complications were identified, including stroke, acute rejection, acute kidney injury requiring hemodialysis, airway dehiscence, and extracorporeal membrane oxygenation 72 hours after surgery. Rates of FTR were calculated as the number of operative mortalities in patients who had complications divided by the number of patients who had any postoperative complications.

RESULTS

Our study population included 16,411 LTx operations performed at 69 transplantation centers. LTx centers were stratified into terciles with average perioperative mortality of 4.0% for low-mortality centers, 6.9% for intermediate-mortality centers, and 12.4% for high-mortality centers. Low-mortality centers had slightly lower complication rates (low, 15.0% vs intermediate, 17.1% vs high, 19.1%; P < .001). Differences in FTR rate were significantly more pronounced (low, 14.9% vs intermediate, 23.9% vs high, 34.2%; P < .001). Multivariable logistic regression and generalized linear models demonstrated an independent association between high FTR rates and high mortality in LTx (P < .001).

CONCLUSIONS

Differences in rates of FTR contribute significantly to per-center variability in mortality after LTx. FTR can serve as a quality metric to identify opportunities for improvement in management of perioperative adverse events.

Type A intramural haematoma secondary to penetrating atherosclerotic ulcer of the ascending aorta

Intramural haematoma and penetrating atherosclerotic ulcer belong to the group of acute aortic syndromes. The combined presentation of both intramural haematoma and a penetrating atherosclerotic ulcer in the ascending aorta is a very rare finding. Here, we present the case of a 72-year-old female, who was admitted to our centre with acute chest and back pain. She was diagnosed with type A intramural haematoma secondary to a penetrating atherosclerotic ulcer of the ascending aorta, and she underwent subsequent emergent surgical management. The diagnosis was confirmed intraoperatively and histopathologically. This case depicts the dynamic pathophysiological development of acute aortic syndromes and the finding that different entities of acute aortic syndromes may evolve or lead to another.

Protocol of a randomised controlled trial in cardiac surgical patients with endothelial dysfunction aimed to prevent postoperative acute kidney injury by administering nitric oxide gas

INTRODUCTION

Postoperative acute kidney injury (AKI) is a common complication in cardiac surgery. Levels of intravascular haemolysis are strongly associated with postoperative AKI and with prolonged (>90 min) use of cardiopulmonary bypass (CPB). Ferrous plasma haemoglobin released into the circulation acts as a scavenger of nitric oxide (NO) produced by endothelial cells. Consequently, the vascular bioavailability of NO is reduced, leading to vasoconstriction and impaired renal function. In patients with cardiovascular risk factors, the endothelium is dysfunctional and cannot replenish the NO deficit. A previous clinical study in young cardiac surgical patients with rheumatic fever, without evidence of endothelial dysfunction, showed that supplementation of NO gas decreases AKI by converting ferrous plasma haemoglobin to ferric methaemoglobin, thus preserving vascular NO. In this current trial, we hypothesised that 24 hours administration of NO gas will reduce AKI following CPB in patients with endothelial dysfunction.

METHODS

This is a single-centre, randomised (1:1) controlled, parallel-arm superiority trial that includes patients with endothelial dysfunction, stable kidney function and who are undergoing cardiac surgery procedures with an expected CPB duration >90 min. After randomisation, 80 parts per million (ppm) NO (intervention group) or 80 ppm nitrogen (N2, control group) are added to the gas mixture. Test gases (N2 or NO) are delivered during CPB and for 24 hours after surgery. The primary study outcome is the occurrence of AKI among study groups. Key secondary outcomes include AKI severity, occurrence of renal replacement therapy, major adverse kidney events at 6 weeks after surgery and mortality. We are recruiting 250 patients, allowing detection of a 35% AKI relative risk reduction, assuming a two-sided error of 0.05.

ETHICS AND DISSEMINATION

The Partners Human Research Committee approved this trial. Recruitment began in February 2017. Dissemination plans include presentations at scientific conferences, scientific publications and advertising flyers and posters at Massachusetts General Hospital.

TRIAL REGISTRATION NUMBER

NCT02836899.

Correlation of cardiopulmonary bypass duration with acute renal failure after cardiac surgery

OBJECTIVES

Prolonged cardiopulmonary bypass (CPB) is recognized as a risk factor for acute renal failure (ARF), but the dose effect of time on bypass is unknown. We therefore examined the risk of ARF associated with increasing CPB time stratified by preoperative renal function.

METHODS

A retrospective analysis was performed on 3889 patients undergoing cardiac surgery on CPB without circulatory arrest between 2011 and 2017 excluding those with a diagnosis of dialysis-dependent renal failure and those who had an intra-aortic balloon pump. Postoperative ARF was defined as a 3-fold increase in creatinine level, creatinine level > 4 mg/dL, or requirement for dialysis. A logistic regression model was built to identify predictors of ARF and to determine the probability of ARF.

RESULTS

Postoperative ARF occurred in 72 patients (2%) overall. Of 100 patients with an estimated glomerular filtration rate <30 mL/min/1.73 m², 22% developed ARF, of which 16 required dialysis. Thirty-day mortality was 31% for those with ARF compared with <1% for those without ARF (P < .01). Risk factors for ARF included obesity (odds ratio, 3.03; P < .01), increasing preoperative creatinine level (odds ratio, 4.21; P < .01), CPB time scaled by a factor of 10 minutes (odds ratio, 1.06; P = .04), and postoperative transfusion (odds ratio, 11.94; P < .01). The adjusted probability of ARF as a function of CPB time was determined and stratified by preoperative glomerular filtration rate.

CONCLUSIONS

Increasing CPB duration is associated with postoperative ARF, particularly among those with preoperative renal impairment. For patients with an estimated glomerular filtration rate <30 mL/min/1.73 m² the risk increases exponentially with time.

Pain management and safety profiles after preoperative vs postoperative thoracic epidural insertion for bilateral lung transplantation

OBJECTIVE

Thoracic epidural analgesia provides effective pain control after lung transplantation; however, the optimal timing of placement is controversial. We sought to compare pain control and pulmonary and epidural morbidity between patients receiving preoperative vs postoperative epidurals.

METHODS

Institutional records were reviewed for patients undergoing a bilateral lung transplant via a bilateral anterior thoracotomy with transverse sternotomy incision between January 2014 and January 2017. Pain control was measured using visual analog scale pain scores (0-10). Pulmonary complications included a composite of pneumonia, prolonged intubation, and reintubation/tracheostomy.

RESULTS

Among 103 patients, 72 (70%) had an epidural placed preoperatively and 31 (30%) had an epidural placed within 72 hours posttransplant. There were no differences in the rates of cardiopulmonary bypass (3% vs 0%, P = 0.59); however, patients with a preoperative epidural were less likely to be placed on extracorporeal membrane oxygenation intraoperatively (25% vs 52%, P = 0.01). Pain control was similar at 24 hours (1.2 vs 1.7, P = 0.05); however, patients with a preoperative epidural reported lower pain scores at 48 (1.2 vs 2.1, P = 0.02) and 72 hours posttransplant (0.8 vs 1.7, P = 0.02). There were no differences in primary graft dysfunction (42% vs 56%, P = 0.28), length of mechanical ventilation (19.5 vs 24 hours, P = 0.18), or adverse pulmonary events (33% vs 52%, P = 0.12). No adverse events including epidural hematoma, paralysis, or infection resulted from epidural placement.

CONCLUSION

Preoperative thoracic epidural placement provides improved analgesia without increased morbidity following lung transplantation.

Single- Versus Double-Lung Transplantation in Pulmonary Fibrosis: Impact of Age and Pulmonary Hypertension

BACKGROUND

Double-lung transplantation (DLT) has better long-term outcomes compared with single-lung transplantation (SLT) in pulmonary fibrosis. However, controversy persists about whether older patients or patients with high lung allocation scores would benefit from DLT. Moreover, the degree of pulmonary hypertension in which SLT should be avoided is unknown.

METHODS

A retrospective analysis using the United Network for Organ Sharing database was performed in all recipients of lung transplants for pulmonary fibrosis. Kaplan-Meier survival for SLT versus DLT was compared and stratified by age, allocation score, and mean pulmonary artery pressure. Cox regression and propensity-matching analyses were performed.

RESULTS

Between 1987 and 2015; 9,191 of 29,779 lung transplants were performed in pulmonary fibrosis. Ten-year survival rates were 55% for DLT and 32% for SLT (p < 0.001). When stratified by age, DLT recipients had improved survival at all age cutoffs, except age ≥70 years. In addition, DLT recipients had improved survival across all lung allocation scores (<45, ≥45, ≥60, ≥75) and all pulmonary artery pressure categories (<25, ≥25, ≥30, ≥40 mm Hg). Among DLT recipients, pulmonary artery pressure and allocation score did not affect survival. Among SLT recipients, a pressure ≥25 mm Hg did not influence survival. Conversely, patients with a pressure ≥30 mm Hg and an allocation score ≥45 had decreased survival. On Cox regression and on propensity matching, DLT had improved survival compared with SLT.

CONCLUSIONS

In pulmonary fibrosis, DLT has improved survival compared with SLT and should be considered the procedure of choice in patients younger than 70 years of age. SLT in patients with mean pulmonary artery pressure ≥30 mm Hg and an allocation score ≥45 should be discouraged.

Aortic valve replacement associated with survival in severe regurgitation and low ejection fraction

OBJECTIVES

Although guidelines support aortic valve replacement (AVR) in patients with severe aortic regurgitation (AR) and left ventricular ejection fraction (LVEF) <50%, severe left ventricular dysfunction (LVEF <35%) is thought to confer high surgical risk. We sought to determine if a survival benefit exists with AVR compared with medical management in this high-risk, relatively rare population.

METHODS

A large institutional echocardiography database was queried to identify patients with severe AR and LVEF <35%. Manual chart review was performed. Due to small sample size and population heterogeneity, corrected group prognosis method was applied, which calculates the adjusted survival curve for each individual using fitted Cox proportional hazard model. Average survival adjusted for comorbidities and age was then calculated using the weighted average of the individual survival curves.

RESULTS

Initially, 2 54 614 echocardiograms were considered, representing 1 45 785 unique patients, of which 40 patients met inclusion criteria. Of those, 18 (45.0%) underwent AVR and 22 (55.0%) were managed medically. Absolute mortality was 27.8% in the AVR group and 91.2% in the medical management group. After multivariate adjustment, end-stage renal disease (HR=17.633, p=0.0335) and peripheral arterial disease (HR=6.050, p=0.0180) were associated with higher mortality. AVR was associated with lower mortality (HR=0.143, p=0.0490). Mean follow-up time of the study cohort was 6.58 years, and mean survival for patients undergoing AVR was 6.31 years.

CONCLUSIONS

Even after adjustment for clinical characteristics and patient age, AVR is associated with higher survival for patients with low LVEF and severe AR. Although treatment selection bias cannot be completely eliminated by this analysis, these results provide some evidence that surgery may be associated with prolonged survival in this high-risk patient group.

Impact of Left Ventricular to Mitral Valve Ring Mismatch on Recurrent Ischemic Mitral Regurgitation After Ring Annuloplasty

BACKGROUND

In ischemic mitral regurgitation (IMR), ring annuloplasty is associated with a significant rate of recurrent MR. Ring size is based on intertrigonal distance without consideration of left ventricular (LV) size. However, LV size is an important determinant of mitral valve (MV) leaflet tethering before and after repair. We aimed to determine whether LV-MV ring mismatch (mismatch of LV size relative to ring size) is associated with recurrent MR in patients with IMR after restrictive ring annuloplasty.

METHODS

Patients with moderate or severe IMR from the 2 Cardiothoracic Surgical Trials Network IMR trials who received MV repair were examined at 1 year after surgery. Baseline LV size was assessed by LV end-diastolic dimension and LV end-systolic dimension (LVESd). LV-MV ring mismatch was calculated as the ratio of LV to ring size (LV end-diastolic dimension/ring size and LVESd/ring size).

RESULTS

At 1 year after ring annuloplasty, 45 of 214 patients with MV repair (21%) had moderate or greater MR. In univariable logistic regression analysis, larger LVESd (P=0.02) and LVESd/ring size (P=0.007) were associated with recurrent MR. In multivariable models adjusted for age, sex, baseline LV ejection fraction, and severe IMR, only LVESd/ring size (odd ratio per 0.5 increase, 2.20; 95% confidence interval, 1.05-4.62; P=0.038) remained significantly associated with 1-year MR recurrence.

CONCLUSIONS

LV-MV ring size mismatch is associated with increased risk of MR recurrence. This finding may be helpful in guiding choice of ring size to prevent recurrent MR in patients undergoing MV repair and in identifying patients who may benefit from MV repair with additional subvalvular intervention or MV replacement rather than repair alone.

CLINICAL TRIAL REGISTRATION

URL:http://clinicaltrials.gov. Unique identifiers: NCT00806988 and NCT00807040.