Trimmed central venous catheters do not increase endothelial injury in an ovine model.

INTRODUCTION: Central venous catheters (CVCs) are often trimmed during heart transplantation and pediatric cardiac surgery. However, the risk of endothelial injury caused by the cut tip of the CVC has not been evaluated. We hypothesized that there is no difference in the degree of endothelial injury associated with trimmed CVCs versus standard untrimmed CVCs. METHODS: In four adult male sheep, the left external jugular vein was exposed in three segments, one designated for an untouched control group, one for the trimmed CVC group, and one for the untrimmed CVC group. Trimmed and untrimmed CVC tips were rotated circumferentially within their respective segments to abrade the lumen of the vein. The vein samples were explanted, and two representative sections from each sample were analyzed using hematoxylin and eosin (H&E) staining, as well as with immunohistochemistry against CD31, von Willebrand factor (vWF), endothelial nitric oxide synthase (eNOS), and caveolin. Higher immunohistochemical stain distributions and intensities are associated with normal health and function of the venous endothelium. Data are presented as counts with percentages or as means with standard error. RESULTS: H&E staining revealed no evidence of endothelial injury in 6/8 (75%) samples from the untouched control group, and no injury in 4/8 (50%) samples from both the trimmed and untrimmed CVC groups (p = 0.504). In all remaining samples from each group, only mild endothelial injury was observed. Immunohistochemical analysis comparing trimmed CVCs versus untrimmed CVCs revealed no difference in the percentage of endothelial cells staining positive for CD31 (57.5% ± 7.2% vs 55.0% ± 9.2%, p = 0.982), vWF (73.8% ± 8.0% vs 62.5% ± 9.6%, p = 0.579), eNOS (66.3% ± 4.2% vs 63.8% ± 7.5%, p = 0.962), and caveolin (53.8% ± 5.0% vs 51.3% ± 4.4%, p = 0.922). There were no significant differences between the groups in the distributions of stain intensity for CD31, vWF, eNOS, and caveolin. CONCLUSION: Trimmed CVCs do not increase endothelial injury compared to standard untrimmed CVCs.

Force Profiles of Single Ventricle Atrioventricular Leaflets in Response to Annular Dilation and Leaflet Tethering.

We sought to understand how leaflet forces change in response to annular dilation and leaflet tethering (LT) in single ventricle physiology. Explanted fetal bovine tricuspid valves were sutured onto image-derived annuli and ventricular mounts. Control valves (CON) were secured to a size-matched hypoplastic left heart syndrome (HLHS)-type annulus and compared to: (1) normal tricuspid valves secured to a size-matched saddle-shaped annulus, (2) HLHS-type annulus with LT, (3) HLHS-type annulus with annular dilation (dilation valves), or (4) a combined disease model with both dilation and tethering (disease valves). The specimens were tested in a systemic heart simulator at various single ventricle physiologies. Leaflet forces were measured using optical strain sensors sutured to each leaflet edge. Average force in the anterior leaflet was 43.2% lower in CON compared to normal tricuspid valves (P < 0.001). LT resulted in a 6.6% increase in average forces on the anterior leaflet (P = 0.04), 10.7% increase on the posterior leaflet (P = 0.03), and 14.1% increase on the septal leaflet (P < 0.001). In dilation valves, average septal leaflet forces increased relative to the CON by 42.2% (P = 0.01). In disease valves, average leaflet forces increased by 54.8% in the anterior leaflet (P < 0.001), 37.6% in the posterior leaflet (P = 0.03), and 79.9% in the septal leaflet (P < 0.001). The anterior leaflet experiences the highest forces in the normal tricuspid annulus under single ventricle physiology conditions. Annular dilation resulted in an increase in forces on the septal leaflet and LT resulted in an increase in forces across all 3 leaflets. Annular dilation and LT combined resulted in the largest increase in leaflet forces across all 3 leaflets.

FDA Emergency Use Authorization-Approved Novel Coronavirus Disease 2019, Pressure-Regulated, Mechanical Ventilator Splitter That Enables Differential Compliance Multiplexing.

Infection with the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), may cause viral pneumonia and acute respiratory distress syndrome (ARDS). Treatment of ARDS often requires mechanical ventilation and may take weeks for resolution. In areas with a large outbreaks, there may be shortages of ventilators available. While rudimentary methods for ventilator splitting have been described, given the range of independent ventilatory settings required for each patient, this solution is suboptimal. Here, we describe a device that can split a ventilator among up to four patients while allowing for individualized settings. The device has been validated in vitro and in vivo .

DynaRing: A Patient-Specific Mitral Annuloplasty Ring With Selective Stiffness Segments.

Annuloplasty ring choice and design are critical to the long-term efficacy of mitral valve (MV) repair. DynaRing is a selectively compliant annuloplasty ring composed of varying stiffness elastomer segments, a shape-set nitinol core, and a cross diameter filament. The ring provides sufficient stiffness to stabilize a diseased annulus while allowing physiological annular dynamics. Moreover, adjusting elastomer properties provides a mechanism for effectively tuning key MV metrics to specific patients. We evaluate the ring embedded in porcine valves with an ex-vivo left heart simulator and perform a 150 million cycle fatigue test via a custom oscillatory system. We present a patient-specific design approach for determining ring parameters using a finite element model optimization and patient MRI data. Ex-vivo experiment results demonstrate that motion of DynaRing closely matches literature values for healthy annuli. Findings from the patient-specific optimization establish DynaRing's ability to adjust the anterior-posterior and intercommissural diameters and saddle height by up to 8.8%, 5.6%, 19.8%, respectively, and match a wide range of patient data.

Electrophysiologic Conservation of Epicardial Conduction Dynamics After Myocardial Infarction and Natural Heart Regeneration in Newborn Piglets.

Newborn mammals, including piglets, exhibit natural heart regeneration after myocardial infarction (MI) on postnatal day 1 (P1), but this ability is lost by postnatal day 7 (P7). The electrophysiologic properties of this naturally regenerated myocardium have not been examined. We hypothesized that epicardial conduction is preserved after P1 MI in piglets. Yorkshire-Landrace piglets underwent left anterior descending coronary artery ligation at age P1 (n = 6) or P7 (n = 7), After 7 weeks, cardiac magnetic resonance imaging was performed with late gadolinium enhancement for analysis of fibrosis. Epicardial conduction mapping was performed using custom 3D-printed high-resolution mapping arrays. Age- and weight-matched healthy pigs served as controls (n = 6). At the study endpoint, left ventricular (LV) ejection fraction was similar for controls and P1 pigs (46.4 ± 3.0% vs. 40.3 ± 4.9%, p = 0.132), but significantly depressed for P7 pigs (30.2 ± 6.6%, p < 0.001 vs. control). The percentage of LV myocardial volume consisting of fibrotic scar was 1.0 ± 0.4% in controls, 9.9 ± 4.4% in P1 pigs (p = 0.002 vs. control), and 17.3 ± 4.6% in P7 pigs (p < 0.001 vs. control, p = 0.007 vs. P1). Isochrone activation maps and apex activation time were similar between controls and P1 pigs (9.4 ± 1.6 vs. 7.8 ± 0.9 ms, p = 0.649), but significantly prolonged in P7 pigs (21.3 ± 5.1 ms, p < 0.001 vs. control, p < 0.001 vs. P1). Conduction velocity was similar between controls and P1 pigs (1.0 ± 0.2 vs. 1.1 ± 0.4 mm/ms, p = 0.852), but slower in P7 pigs (0.7 ± 0.2 mm/ms, p = 0.129 vs. control, p = 0.052 vs. P1). Overall, our data suggest that epicardial conduction dynamics are conserved in the setting of natural heart regeneration in piglets after P1 MI.

A Novel Device for Intraoperative Direct Visualization of a Pressurized Root in Aortic Valve Repair.

PURPOSE: One major challenge in generating reproducible aortic valve (AV) repair results is the inability to assess AV morphology under physiologic pressure. A transparent intraoperative AV visualization device was designed and manufactured. DESCRIPTION: This device comprises an open proximal end, a cantilevered edge to allow attachment of the device to the aorta or graft, a distal viewing surface, and 2 side ports for fluid delivery and air removal. EVALUATION: The performance of the device was evaluated ex vivo using normal porcine AV in situ (n = 3), porcine AV after valve-sparing aortic root replacement (VSARR) (n = 3), porcine pulmonary valve in the Ross procedure (n = 3), and in 3 patients who underwent VSARR. AV morphology was clearly visualized using the device in all experiments. In human subjects, the use of this device successfully showed cusp prolapse after the initial VSARR and effectively guided additional cusp repair. CONCLUSIONS: This device successfully allows for direct visual assessment of the AV apparatus under physiologic pressure. The use of this device can potentially increase the adoptability of AV repair in clinical practice.

Ex vivo biomechanical analysis of flexible versus rigid annuloplasty rings in mitral valves using a novel annular dilation system.

BACKGROUND: Mitral annuloplasty rings restore annular dimensions to increase leaflet coaptation, serving a fundamental component in mitral valve repair. However, biomechanical evaluations of annuloplasty rings are lacking. We aim to biomechanically analyze flexible and rigid annuloplasty rings using an ex vivo mitral annular dilation model. METHODS: Juvenile porcine mitral valves (n = 4) with intercommissural distance of 28 mm were dilated to intercommissural distances of 40 mm using a 3D-printed dilator and were sewn to an elastic mount. Fiber bragg grating sensors were anchored to native chordae to measure chordal forces. The valves were repaired using size 28 rigid and flexible annuloplasty rings in a random order. Hemodynamic data, echocardiography, and chordal force measurements were collected. RESULTS: Mitral annular dilation resulted in decreased leaflet coaptation height and increased mitral regurgitation fraction. Both the flexible and rigid annuloplasty rings effectively increased leaflet coaptation height compared to that post dilation. Rigid ring annuloplasty repair significantly decreased the mitral regurgitation fraction. Flexible annuloplasty ring repair reduced the chordal rate of change of force (7.1 ± 4.4 N/s versus 8.6 ± 5.9 N/s, p = 0.02) and peak force (0.6 ± 0.5 N versus 0.7 ± 0.6 N, p = 0.01) compared to that from post dilation. Rigid annuloplasty ring repair was associated with higher chordal rate of change of force (9.8 ± 5.8 N/s, p = 0.0001) and peak force (0.7 ± 0.5 N, p = 0.01) compared to that after flexible ring annuloplasty repair. CONCLUSIONS: Both rigid and flexible annuloplasty rings are effective in increasing mitral leaflet coaptation height. Although the rigid annuloplasty ring was associated with slightly higher chordal stress compared to that of the flexible annuloplasty ring, it was more effective in mitral regurgitation reduction. This study may help direct the design of an optimal annuloplasty ring to further improve patient outcomes.

Natural cardiac regeneration conserves native biaxial left ventricular biomechanics after myocardial infarction in neonatal rats.

After myocardial infarction (MI), adult mammals exhibit scar formation, adverse left ventricular (LV) remodeling, LV stiffening, and impaired contractility, ultimately resulting in heart failure. Neonatal mammals, however, are capable of natural heart regeneration after MI. We hypothesized that neonatal cardiac regeneration conserves native biaxial LV mechanics after MI. Wistar rat neonates (1 day old, n = 46) and adults (8-10 weeks old, n = 20) underwent sham surgery or permanent left anterior descending coronary artery ligation. At 6 weeks after neonatal MI, Masson's trichrome staining revealed negligible fibrosis. Echocardiography for the neonatal MI (n = 15) and sham rats (n = 14) revealed no differences in LV wall thickness or chamber diameter, and both groups had normal ejection fraction (72.7% vs 77.5%, respectively, p = 0.1946). Biaxial tensile testing revealed similar stress-strain curves along both the circumferential and longitudinal axes across a full range of physiologic stresses and strains. The circumferential modulus (267.9 kPa vs 274.2 kPa, p = 0.7847), longitudinal modulus (269.3 kPa vs 277.1 kPa, p = 0.7435), and maximum shear stress (3.30 kPa vs 3.95 kPa, p = 0.5418) did not differ significantly between the neonatal MI and sham groups, respectively. In contrast, transmural scars were observed at 4 weeks after adult MI. Adult MI hearts (n = 7) exhibited profound LV wall thinning (p < 0.0001), chamber dilation (p = 0.0246), and LV dysfunction (ejection fraction 45.4% vs 79.7%, p < 0.0001) compared to adult sham hearts (n = 7). Adult MI hearts were significantly stiffer than adult sham hearts in both the circumferential (321.5 kPa vs 180.0 kPa, p = 0.0111) and longitudinal axes (315.4 kPa vs 172.3 kPa, p = 0.0173), and also exhibited greater maximum shear stress (14.87 kPa vs 3.23 kPa, p = 0.0162). Our study is the first to show that native biaxial LV mechanics are conserved after neonatal heart regeneration following MI, thus adding biomechanical support for the therapeutic potential of cardiac regeneration in the treatment of ischemic heart disease.

Biomechanical engineering analysis of an acute papillary muscle rupture disease model using an innovative 3D-printed left heart simulator.

OBJECTIVES: The severity of acute papillary muscle (PM) rupture varies according to the extent and site of the rupture. However, the haemodynamic effects of different rupture variations are still poorly understood. Using a novel ex vivo model, we sought to study acute PM rupture to improve clinical management. METHODS: Using porcine mitral valves (n = 32) mounted within an ex vivo left heart simulator, PM rupture was simulated. The mitral valve was divided into quadrants for analysis according to the PM heads. Acute PM rupture was simulated by incrementally cutting from 1/3 to the total number of chordae arising from 1 PM head of interest. Haemodynamic parameters were measured. RESULTS: Rupture >2/3 of the chordae from 1 given PM head or regurgitation fraction >60% led to markedly deteriorated haemodynamics. Rupture at the anterolateral PM had a stronger negative effect on haemodynamics than rupture at the posteromedial PM. Rupture occurring at the anterior head of the anterolateral PM led to more marked haemodynamic instability than rupture occurring at the other PM heads. CONCLUSIONS: The haemodynamic effects of acute PM rupture vary considerably according to the site and extent of the rupture. Rupture of ≤2/3 of chordae from 1 PM head or rupture at the posteromedial PM lead to less marked haemodynamics effects, suggesting a higher likelihood of tolerating surgery. Rupture at the anterolateral PM, specifically the anterior head, rupture of >2/3 of chordae from 1 PM head or regurgitation fraction >60% led to marked haemodynamic instability, suggesting the potential benefit from bridging strategies prior to surgery.

Novel bicuspid aortic valve model with aortic regurgitation for hemodynamic status analysis using an ex vivo simulator.

OBJECTIVE: The objective was to design and evaluate a clinically relevant, novel ex vivo bicuspid aortic valve model that mimics the most common human phenotype with associated aortic regurgitation. METHODS: Three bovine aortic valves were mounted asymmetrically in a previously validated 3-dimensional-printed left heart simulator. The non-right commissure and the non-left commissure were both shifted slightly toward the left-right commissure, and the left and right coronary cusps were sewn together. The left-right commissure was then detached and reimplanted 10 mm lower than its native height. Free margin shortening was used for valve repair. Hemodynamic status, high-speed videography, and echocardiography data were collected before and after the repair. RESULTS: The bicuspid aortic valve model was successfully produced and repaired. High-speed videography confirmed prolapse of the fused cusp of the baseline bicuspid aortic valve models in diastole. Hemodynamic and pressure data confirmed accurate simulation of diseased conditions with aortic regurgitation and the subsequent repair. Regurgitant fraction postrepair was significantly reduced compared with that at baseline (14.5 ± 4.4% vs 28.6% ± 3.4%; P = .037). There was no change in peak velocity, peak gradient, or mean gradient across the valve pre- versus postrepair: 293.3 ± 18.3 cm/sec versus 325.3 ± 58.2 cm/sec (P = .29), 34.3 ± 4.2 mm Hg versus 43.3 ± 15.4 mm Hg (P = .30), and 11 ± 1 mm Hg versus 9.3 ± 2.5 mm Hg (P = .34), respectively. CONCLUSIONS: An ex vivo bicuspid aortic valve model was designed that recapitulated the most common human phenotype with aortic regurgitation. These valves were successfully repaired, validating its potential for evaluating valve hemodynamics and optimizing surgical repair for bicuspid aortic valves.

A neonatal leporine model of age-dependent natural heart regeneration after myocardial infarction.

OBJECTIVES: Neonatal rodents and piglets naturally regenerate the injured heart after myocardial infarction. We hypothesized that neonatal rabbits also exhibit natural heart regeneration after myocardial infarction. METHODS: New Zealand white rabbit kits underwent sham surgery or left coronary ligation on postnatal day 1 (n = 94), postnatal day 4 (n = 11), or postnatal day 7 (n = 52). Hearts were explanted 1 day postsurgery to confirm ischemic injury, at 1 week postsurgery to assess cardiomyocyte proliferation, and at 3 weeks postsurgery to assess left ventricular ejection fraction and scar size. Data are presented as mean ± standard deviation. RESULTS: Size of ischemic injury as a percentage of left ventricular area was similar after myocardial infarction on postnatal day 1 versus on postnatal day 7 (42.3% ± 5.4% vs 42.3% ± 4.7%, P = .9984). Echocardiography confirmed severely reduced ejection fraction at 1 day after postnatal day 1 myocardial infarction (33.7% ± 5.3% vs 65.2% ± 5.5% for postnatal day 1 sham, P = .0001), but no difference at 3 weeks after postnatal day 1 myocardial infarction (56.0% ± 4.0% vs 58.0% ± 3.3% for postnatal day 1 sham, P = .2198). Ejection fraction failed to recover after postnatal day 4 myocardial infarction (49.2% ± 1.8% vs 58.5% ± 5.8% for postnatal day 4 sham, P = .0109) and postnatal day 7 myocardial infarction (39.0% ± 7.8% vs 60.2% ± 5.0% for postnatal day 7 sham, P &lt; .0001). At 3 weeks after infarction, fibrotic scar represented 5.3% ± 1.9%, 14.3% ± 4.9%, and 25.4% ± 13.3% of the left ventricle area in the postnatal day 1, postnatal day 4, and postnatal day 7 groups, respectively. An increased proportion of peri-infarct cardiomyocytes expressed Ki67 (15.9% ± 1.8% vs 10.2% ± 0.8%, P = .0039) and aurora B kinase (4.0% ± 0.9% vs 1.5% ± 0.6%, P = .0088) after postnatal day 1 myocardial infarction compared with sham, but no increase was observed after postnatal day 7 myocardial infarction. CONCLUSIONS: A neonatal leporine myocardial infarction model reveals that newborn rabbits are capable of age-dependent natural heart regeneration.

Artificial papillary muscle device for off-pump transapical mitral valve repair.

OBJECTIVE: New transapical minimally invasive artificial chordae implantation devices are a promising alternative to traditional open-heart repair, with the potential for decreased postoperative morbidity and reduced recovery time. However, these devices can place increased stress on the artificial chordae. We designed an artificial papillary muscle to alleviate artificial chordae stresses and thus increase repair durability. METHODS: The artificial papillary muscle device is a narrow elastic column with an inner core that can be implanted during the minimally invasive transapical procedure via the same ventricular incision site. The device was 3-dimensionally printed in biocompatible silicone for this study. To test efficacy, porcine mitral valves (n = 6) were mounted in a heart simulator, and isolated regurgitation was induced. Each valve was repaired with a polytetrafluoroethylene suture with apical anchoring followed by artificial papillary muscle anchoring. In each case, a high-resolution Fiber Bragg Grating sensor recorded forces on the suture. RESULTS: Hemodynamic data confirmed that both repairs-with and without the artificial papillary muscle device-were successful in eliminating mitral regurgitation. Both the peak artificial chordae force and the rate of change of force at the onset of systole were significantly lower with the device compared with apical anchoring without the device (P < .001 and P < .001, respectively). CONCLUSIONS: Our novel artificial papillary muscle could integrate with minimally invasive repairs to shorten the artificial chordae and behave as an elastic damper, thus reducing sharp increases in force. With our device, we have the potential to improve the durability of off-pump transapical mitral valve repair procedures.

From hardware store to hospital: a COVID-19-inspired, cost-effective, open-source, in vivo-validated ventilator for use in resource-scarce regions.

Resource-scarce regions with serious COVID-19 outbreaks do not have enough ventilators to support critically ill patients, and these shortages are especially devastating in developing countries. To help alleviate this strain, we have designed and tested the accessible low-barrier in vivo-validated economical ventilator (ALIVE Vent), a COVID-19-inspired, cost-effective, open-source, in vivo-validated solution made from commercially available components. The ALIVE Vent operates using compressed oxygen and air to drive inspiration, while two solenoid valves ensure one-way flow and precise cycle timing. The device was functionally tested and profiled using a variable resistance and compliance artificial lung and validated in anesthetized large animals. Our functional test results revealed its effective operation under a wide variety of ventilation conditions defined by the American Association of Respiratory Care guidelines for ventilator stockpiling. The large animal test showed that our ventilator performed similarly if not better than a standard ventilator in maintaining optimal ventilation status. The FiO2, respiratory rate, inspiratory to expiratory time ratio, positive-end expiratory pressure, and peak inspiratory pressure were successfully maintained within normal, clinically validated ranges, and the animals were recovered without any complications. In regions with limited access to ventilators, the ALIVE Vent can help alleviate shortages, and we have ensured that all used materials are publicly available. While this pandemic has elucidated enormous global inequalities in healthcare, innovative, cost-effective solutions aimed at reducing socio-economic barriers, such as the ALIVE Vent, can help enable access to prompt healthcare and life saving technology on a global scale and beyond COVID-19. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s42242-021-00164-1.

Heart Valve Biomechanics: The Frontiers of Modeling Modalities and the Expansive Capabilities of Ex Vivo Heart Simulation.

The field of heart valve biomechanics is a rapidly expanding, highly clinically relevant area of research. While most valvular pathologies are rooted in biomechanical changes, the technologies for studying these pathologies and identifying treatments have largely been limited. Nonetheless, significant advancements are underway to better understand the biomechanics of heart valves, pathologies, and interventional therapeutics, and these advancements have largely been driven by crucial in silico, ex vivo, and in vivo modeling technologies. These modalities represent cutting-edge abilities for generating novel insights regarding native, disease, and repair physiologies, and each has unique advantages and limitations for advancing study in this field. In particular, novel ex vivo modeling technologies represent an especially promising class of translatable research that leverages the advantages from both in silico and in vivo modeling to provide deep quantitative and qualitative insights on valvular biomechanics. The frontiers of this work are being discovered by innovative research groups that have used creative, interdisciplinary approaches toward recapitulating in vivo physiology, changing the landscape of clinical understanding and practice for cardiovascular surgery and medicine.

Biomechanical engineering comparison of four leaflet repair techniques for mitral regurgitation using a novel 3-dimensional-printed left heart simulator.

OBJECTIVE: Mitral valve repair is the gold standard treatment for degenerative mitral regurgitation; however, a multitude of repair techniques exist with little quantitative data comparing these approaches. Using a novel ex vivo model, we sought to evaluate biomechanical differences between repair techniques. METHODS: Using porcine mitral valves mounted within a custom 3-dimensional-printed left heart simulator, we induced mitral regurgitation using an isolated P2 prolapse model by cutting primary chordae. Next, we repaired the valves in series using the edge-to-edge technique, neochordoplasty, nonresectional remodeling, and classic leaflet resection. Hemodynamic data and chordae forces were measured and analyzed using an incomplete counterbalanced repeated measures design with the healthy pre-prolapse valve as a control. RESULTS: With the exception of the edge-to-edge technique, all repair methods effectively corrected mitral regurgitation, returning regurgitant fraction to baseline levels (baseline 11.9% ± 3.7%, edge-to-edge 22.5% ± 6.9%, nonresectional remodeling 12.3% ± 3.0%, neochordal 13.4% ± 4.8%, resection 14.7% ± 5.5%, P < 0.01). Forces on the primary chordae were minimized using the neochordal and nonresectional techniques whereas the edge-to-edge and resectional techniques resulted in significantly elevated primary forces. Secondary chordae forces also followed this pattern, with edge-to-edge repair generating significantly higher secondary forces and leaflet resection trending higher than the nonresectional and neochord repairs. CONCLUSIONS: Although multiple methods of degenerative mitral valve repair are used clinically, their biomechanical properties vary significantly. Nonresectional techniques, including leaflet remodeling and neochordal techniques, appear to result in lower chordal forces in this ex vivo technical engineering model.

Ex Vivo Analysis of a Porcine Bicuspid Aortic Valve and Aneurysm Disease Model.

We identified an extremely rare congenital porcine type 0 lateral bicuspid aortic valve from a fresh porcine heart. Using a 3-dimensionally printed ex vivo left heart simulator, we analyzed valvular hemodynamics at baseline, in an aortic aneurysm disease model, and after valve-sparing root replacement. We showed that bicuspid aortic valve regurgitation due to aortic aneurysm can be successfully repaired without significant hemodynamic impairment using the valve-sparing root replacement technique in an individualized approach. Our results provide direct hemodynamic evidence supporting the use of valve-sparing root replacement for patients with bicuspid aortic valve regurgitation.

Economic Analysis and Long-term Follow-up of Distant Referral for Degenerative Mitral Valve Repair.

BACKGROUND: Despite the superiority of mitral valve repair (MVr) over replacement for degenerative disease, repair rates vary widely across centers. Traveling to a mitral reference center (MRC) is 1 way to increase the odds of MVr. This study assessed the economic value (quality/cost) and long-term outcomes of distant referral to an MRC. METHODS: Among 746 mitral surgery patients between January 2011 and June 2013, low-risk patients with an ejection fraction greater than 40% undergoing isolated degenerative MVr were identified and included 26 out-of-state (DISTANT) and 104 in-state patients (LOCAL). Short- and long-term outcomes and institutional financial data (including travel expenses) were used to compare groups. National average and MRC-specific MVr rates, clinical outcomes, and marginal value of quality-adjusted life-years collected from The Society of Thoracic Surgeons database and Medicare estimates were used to perform a nationally representative cost-benefit analysis for distant referral. RESULTS: Age, ejection fraction, operative time, blood transfusions, and annuloplasty ring size did not differ between groups. Median charges were $76,022 for LOCAL and $74,171 for DISTANT (P = .35), whereas median payments (including travel expenses) were $57,795 for LOCAL and $58,477 for DISTANT (P = .70). Short- and long-term outcomes were similar between groups and median follow-up was 7.1 years. Estimated 5-year survival was 97% (96% for LOCAL and 100% for DISTANT; P = .24). Cost-benefit analysis showed a net benefit through distant referral to an MRC ranging from $436 to $6078 to the payer and $22,163 to $30,067 to the patient, combining for an estimated $22,599 to $32,528 societal benefit. CONCLUSIONS: These data suggest that distant referral to an MRC is achievable and reasonable.