Practice Patterns in Sternal Closure and Evaluation of Adoption of a Novel Sternal Closure Device.

OBJECTIVE: The technique for sternal closure has remained largely unchanged owing to the efficacy, simplicity, and low cost of stainless-steel sternal wires. Despite their ubiquity, several other closure devices designed to address the complications associated with sternal wires such as sternal bleeding and dehiscence have become popular. We have developed a novel sternal closure device that reduces sternal bleeding and dehiscence. This study quantifies the use of currently available sternal closure devices and determines predicted uptake of the novel device. METHODS: An electronic survey, designed to determine practice patterns for sternal closure, was distributed to 70 US cardiac surgeons. The survey included a discrete choice section in which surgeons evaluated relative value of device attributes including cost, ease of emergent sternal reentry, and dehiscence risk. RESULTS: There were 70 surgeons from 30 states who completed the survey. The most frequent means of sternal closure was straight sternal wires (35.8%), followed by straight sternal wires plus figure-of-8 sternal wires (18.1%), double wires (10.9%), plates (10.2%), and other (25%). The relative utilization shifted from sternal wires to sternal plates as the risk for dehiscence increased. The adoption of the novel closure device was estimated at 34.6%. CONCLUSIONS: The standard stainless-steel sternal wire remains the most common means of sternal reapproximation, but its utilization is lower in patients at high risk for sternal dehiscence. Based on this survey, there is acceptance in the community for a novel sternal closure device designed to address the limitations of traditional sternal closure methods.

Mechanical Analysis of a Novel Sternal Closure System in Static Tensile Loading.

The most common means of sternal closure after sternotomy is stainless steel wire cerclage. These wires, while inexpensive and simple in design, are known to be associated with low strength and sternal dehiscence. In this biomechanical analysis, we compare single sternal wires, double sternal wires, and a novel sternal closure device we have designed to mitigate sternal dehiscence. The device uses polymer grommets at the sternal interfaces to distribute load over a large surface area of bone. Samples of each closure device were installed in a bone model and distracted at a rate of 10 mm/min while tensile forces were continuously measured and compared. Single wires generated the lowest stiffness and strength values, followed by the double wires. The novel device demonstrated significantly higher stiffness and strength at all displacements compared with the single and double wires. Clinical use of this device may result in meaningful reduction in complications associated with the use of standard sternal wires such as sternal separation and fracture.

Successful Resuscitation of Porcine Hearts After 12 and 24 h of Static Cold Storage With Normothermic Ex Situ Perfusion.

Background: Heart transplantation is always an emergency because the transplant needs to occur within 6 h after procurement to prevent primary graft dysfunction. Static cold storage (SCS) is the gold-standard preservation method. This study describes the outcomes of hearts preserved after prolonged SCS (12 and 24 h); those are then resuscitated with a novel normothermic ex situ heart perfusion (NEHP) system. Methods: Anesthetized piglets (n = 10) were used as heart donors. Hearts were procured and stored at 5 °C CoStorSol following standard SCS protocols. Two groups were studied: SCS-12 h and SCS-24 h. After SCS, 8 h of NEHP (37 °C blood-based perfusate) was performed at 0.7-1.0 mL/min/g of cardiac tissue. NEHP parameters were monitored continuously. Results were corroborated with 3 additional hearts transplanted orthotopically in healthy recipients (n = 3) after SCS (24 h) + NEHP (5 h). Recipients were observed for 90 min after weaning off cardiopulmonary bypass support. Results: All hearts (after 12 and 24 h of SCS) regained normal function and metabolism within 10 min and retained it throughout 8 h of NEHP. No differences were observed in NEHP parameters and histopathology between groups. Three hearts were successfully transplanted after a total ~30 h of preservation (24 h of SCS + 5 h of NEHP + 1 h of second cold ischemia time). The 3 recipients were weaned off cardiopulmonary bypass with mild vasopressor support. Conclusions: NEHP has the potential to routinely resuscitate porcine hearts that have undergone SCS for up to 24 h, restoring them to viable function. By objectively assessing heart function before transplant, NEHP may enhance the success rate of transplants. If these resuscitated hearts can be successfully transplanted, it would support the effectiveness of NEHP in ensuring heart viability.

Safety Window for Effective Lesion Crossing in Patients With Chronic Thromboembolic Pulmonary Hypertension.

Background: Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension (CTEPH) is limited by a lack of safe and effective tools for crossing these lesions. We aim to identify a safety window for an intraluminal crossing device in this vascular bed by studying the piercing properties of pulmonary arterial vessel walls and intraluminal CTEPH lesion specimens. As a secondary objective, we also describe the histopathologic features of CTEPH lesions. Methods: Specimens were procured from 9 patients undergoing pulmonary endarterectomy. The specimens were subsampled and identified grossly as arterial wall or intraluminal CTEPH lesions. The force needed for tissue penetration was measured using a 0.38-mm (0.015-in) diameter probe in an ex vivo experimental model developed in our lab. Concurrent histology was also performed. Results: The mean force needed to penetrate the arterial wall and intraluminal CTEPH lesions was 1.75 ± 0.10 N (n = 121) and 0.30 ± 0.04 N (n = 56), respectively (P < .001). Histology confirmed the presence of intimal hyperplasia with calcium and hemosiderin deposition in the arterial wall as well as an old, organized thrombus in the lumen. Conclusions: The pulmonary arterial wall is friable and prone to perforation during instrumentation with workhorse coronary guide wires. However, the results of this study demonstrate that a much lower force is needed for the 0.38-mm (0.015-in) probe to penetrate an intraluminal CTEPH lesion compared to pulmonary arterial intima. This finding suggests the existence of a safety window for lesion-crossing devices, enabling effective balloon pulmonary angioplasty.

Determinants of survival following heart transplantation in adults with congenital heart disease.

BACKGROUND: Adult patients surviving with congenital heart disease (ACHD) is growing. We examine the factors associated with heart transplant outcomes in this challenging population with complex anatomy requiring redo-surgeries. METHODS: We reviewed the United Network for Organ Sharing-Standard Transplant Analysis and Research database and analyzed 35,952 heart transplants from January 1st, 2000, to September 30th, 2018. We compared transplant characteristics for ischemic cardiomyopathy (ICM) (n = 14,236), nonischemic cardiomyopathy (NICM) (n = 20,676), and ACHD (n = 1040). Mean follow-up was 6.20 ± 4.84 years. Kaplan-Meier survival curves and Cox-proportional hazards analysis were used to analyze survival data. RESULTS: Multivariable analysis confirmed that ACHD was associated greater in-hospital death compared to ICM (HR = 0.54, P < 0.001) and NICM (HR = 0.46, P < 0.001). Notable factors associated with increased mortality were history of cerebrovascular disease (HR = 1.11, P = 0.026), prior history of malignancy (HR = 1.12, P = 0.006), pre-transplant biventricular support (HR = 1.12, P = 0.069), postoperative stroke (HR = 1.47, P < 0.001) and postoperative dialysis (HR = 1.71, P < 0.001). ACHD transplants had a longer donor heart ischemic time (P < 0.001) and trend towards more deaths from primary graft dysfunction (P = 0.07). In-hospital deaths were more likely with ACHD and use of mechanical support such as use of right ventricular assist device (HR = 2.20, P = 0.049), biventricular support (HR = 1.62, P < 0.001) and extracorporeal membrane oxygenation (HR = 2.36, P < 0.001). Conditional survival after censoring hospital deaths was significantly higher in ACHD (P < 0.001). CONCLUSION: Heart transplant in ACHD is associated with a higher post-operative mortality given anatomical complexity but a better long-term conditional survival. Normothermic donor heart perfusion may improve outcomes in the ACHD population by reducing the impact of longer ischemic times.

Transcatheter Aortic Valve Replacement for Left Ventricular Assist Device-Related Aortic Regurgitation: The Michigan Medicine Experience.

Background: Aortic regurgitation (AR) is common and detrimental in patients with left ventricular assist devices (LVADs). Off-label use of transcatheter aortic valve replacement (TAVR) has emerged as a potential treatment option. Further data are required regarding the feasibility and outcomes of TAVR to treat AR in LVAD recipients. Methods: A retrospective review of all patients with LVADs who underwent TAVR for the treatment of AR at a single center was performed. All echocardiograms were independently reviewed to ensure accuracy. Results: Eleven patients with continuous-flow LVADs underwent TAVR for AR. All patients had moderate or severe AR with New York Heart Association (NYHA) class III and IV symptoms. Implantation of more than 1 valve was required in 4 (36.3%) patients; 1 patient died during the procedure because of valve migration into the left ventricle and 1 patient died in-hospital after TAVR. Of 9 (81.8%) patients discharged alive, 8 (72.7%) were alive at 12 months and all survivors had improvement in AR severity, natriuretic peptide levels, left ventricle end-diastolic diameter, and NYHA class. Five (62.5%) survivors had a large improvement (>20 points) in the Kansas City Cardiomyopathy Questionnaire score at 1 year. One survivor experienced heart failure, requiring hospitalization, within 1 year. Conclusions: In this single-center series, TAVR for the treatment of AR in patients with LVADs is technically challenging but feasible in select patients and may produce durable improvements in AR severity, functional status, and quality of life.