Project description:Background:While ventricular assist devices (VADs) remain the cornerstone of mechanical circulatory support (MCS), the total artificial heart (TAH-t) has gained popularity for certain patients in whom VAD support is not ideal. Congenital heart disease (CHD) patients often have barriers to VAD placement due to anatomic and physiological variation and thus can benefit from the TAH-t. The purpose of this study is to analyze the differences in TAH application and outcomes in patients with and without CHD. Methods:The SynCardia Department of Clinical Research provided data upon request for all TAH-t implantations worldwide from December 1985 to October 2019. These patients were divided into two groups by pre-implantation diagnosis of CHD and non-CHD. Results:A total of 1,876 patients were identified. Eighty (4%) of these patients also carried a diagnosis of CHD. There was a higher proportion of children in the CHD cohort (16.3% vs. 2.1%, P<0.001) and this translated into a lower average age amongst the two groups (34±13 vs. 49±13 years, P<0.001). There were also significantly more females in the CHD group (22.8% vs. 12.8%, P=0.010). CHD patients were more likely to be supported with a 50 cc TAH-t (11.3% vs. 4.5%, P=0.005) while all other support characteristics, including duration of support, were similar between the groups. All measured outcomes were similar between CHD and non-CHD patients including positive outcome (alive on device or transplanted), 1-month conditional survival, and rate of Freedom Driver use. Conclusions:TAH-t is an effective means to support patients with CHD. Patients with CHD had similar survival, support characteristics, and frequency of discharge compared to patients without CHD. As MCS continues to grow, its indications broadened, and its contraindications narrowed, more patient populations will see the benefit of the TAH's continuously developing technology.
Project description:BackgroundData are limited on outcomes after heart transplantation in patients bridged-to-transplantation (BTT) with a total artificial heart (TAH-t).MethodsThe UNOS database was used to identify 392 adult patients undergoing heart transplantation after TAH-t BTT between 2005 and 2020. They were compared with 11 014 durable left ventricular assist device (LVAD) BTT patients and 22 348 de novo heart transplants (without any durable VAD or TAH-t BTT) during the same period.ResultsTAH-t BTT patients had increased dialysis dependence compared to LVAD BTT and de novo transplants (24.7% vs. 2.7% vs. 3.8%) and higher levels of baseline creatinine and total bilirubin (all p < .001). After transplantation, TAH-t BTT patients were more likely to die from multiorgan failure in the first year (25.0% vs. 16.1% vs. 16.1%, p = .04). Ten-year survival was inferior in TAH-t BTT patients (TAH-t BTT 53.1%, LVAD BTT 61.8%, De Novo 62.6%, p < .001), while 10-year survival conditional on 1-year survival was similar (TAH-t BTT 66.8%, LVAD BTT 68.7%, De Novo 69.0%, all p > .20). Among TAH-t BTT patients, predictors of 1-year mortality included higher baseline creatinine and total bilirubin, mechanical ventilation, and cumulative center volume <20 cases of heart transplantation involving TAH-t BTT (all p < .05).ConclusionSurvival after TAH-t BTT is acceptable, and patients who survive the early postoperative phase experience similar hazards of mortality over time compared to de novo transplant patients and durable LVAD BTT patients.
Project description:BackgroundHeart transplantation in infants and children is an accepted therapy for end-stage heart failure, but donor organ availability is low and always uncertain. Mechanical circulatory support is another standard option, but there is a lack of intracorporeal devices due to size and functional range. The purpose of this study was to evaluate the in vivo performance of our initial prototype of a pediatric continuous-flow total artificial heart (P-CFTAH), comprising a dual pump with one motor and one rotating assembly, supported by a hydrodynamic bearing.MethodsIn acute studies, the P-CFTAH was implanted in 4 lambs (average weight: 28.7 ± 2.3 kg) via a median sternotomy under cardiopulmonary bypass. Pulmonary and systemic pump performance parameters were recorded.ResultsThe experiments showed good anatomical fit and easy implantation, with an average aortic cross-clamp time of 98 ± 18 minutes. Baseline hemodynamics were stable in all 4 animals (pump speed: 3.4 ± 0.2 krpm; pump flow: 2.1 ± 0.9 liters/min; power: 3.0 ± 0.8 W; arterial pressure: 68 ± 10 mm Hg; left and right atrial pressures: 6 ± 1 mm Hg, for both). Any differences between left and right atrial pressures were maintained within the intended limit of ±5 mm Hg over a wide range of ratios of systemic-to-pulmonary vascular resistance (0.7 to 12), with and without pump-speed modulation. Pump-speed modulation was successfully performed to create arterial pulsation.ConclusionThis initial P-CFTAH prototype met the proposed requirements for self-regulation, performance, and pulse modulation.
Project description:Previous studies have shown that the manufacturer's default preoperative plans for total knee arthroplasty with patient-specific guides require frequent, time-consuming changes by the surgeon. Currently, no research has been done on predicting preoperative plans for orthopedic surgery using machine learning. Therefore, this study aims to evaluate whether artificial intelligence (AI) driven planning tools can create surgeon and patient-specific preoperative plans that require fewer changes by the surgeon. A dataset of 5409 preoperative plans, including the manufacturer's default and the plans corrected by 39 surgeons, was collected. Features were extracted from the preoperative plans that describe the implant sizes, position, and orientation in a surgeon- and patient-specific manner. Based on these features, non-linear regression models were employed to predict the surgeon's corrected preoperative plan. The average number of corrections a surgeon has to make to the preoperative plan generated using AI was reduced by 39.7% compared to the manufacturer's default plan. The femoral and tibial implant size in the manufacturer's plan was correct in 68.4% and 73.1% of the cases, respectively, while the AI-based plan was correct in 82.2% and 85.0% of the cases, respectively, compared to the surgeon approved plan. Our method successfully demonstrated the use of machine learning to create preoperative plans in a surgeon- and patient-specific manner for total knee arthroplasty.
Project description:The SynCardia total artificial heart (TAH) has emerged as an effective, life-saving biventricular replacement system for a wide variety of patients with end-stage heart failure. Although the clinical performance of the TAH is established, modern physiological characterization, in terms of elastance behavior and pressure-volume (PV) characterization has not been defined. Herein, we examine the TAH in terms of elastance using a nonejecting left ventricle, and then characterize the PV relation of the TAH by varying preload and afterload parameters using a Donovan Mock Circulatory System. We demonstrate that the TAH does not operate with time-varying elastance, differing from the human heart. Furthermore, we show that the TAH has a PV relation behavior that also differs from that of the human heart. The TAH does exhibit Starling-like behavior, with output increasing via preload-dependent mechanisms, without reliance on an alteration of inotropic state within the operating window of the TAH. Within our testing range, the TAH is insensitive to variations in afterload; however, this insensitivity has a limit, the limit being the maximum driving pressure of the pneumatic driver. Understanding the physiology of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared with the human heart.
Project description:Optimal vascular access planning begins when the patient is in the predialysis stages of CKD. The choice of optimal vascular access for an individual patient and determining timing of access creation are dependent on a multitude of factors that can vary widely with each patient, including demographics, comorbidities, anatomy, and personal preferences. It is important to consider every patient's ESRD life plan (hence, their overall dialysis access life plan for every vascular access creation or placement). Optimal access type and timing of access creation are also influenced by factors external to the patient, such as surgeon experience and processes of care. In this review, we will discuss the key determinants in optimal access type and timing of access creation for upper extremity arteriovenous fistulas and grafts.
Project description:Complex cyanotic congenital heart diseases with left isomerism are sometimes associated with atrioventricular nodal conduction disturbances that may need permanent pacing. Surgical palliation in such anatomy connecting the superior vena cava to the pulmonary artery precludes a transvenous access for an endocardial pacing lead to the ventricles. Epicardial leads in these patients fail if the pacing thresholds are very high. We report transhepatic permanent ventricular lead implantation for a young boy with heterotaxy complicated by complete heart block.
Project description:For patients who have previously undergone total laryngectomy and a permanent tracheostomy, median full sternotomy is not the ideal surgical approach because of the substantially increased risk of sternal wound complications and tracheal injuries. We present a case in which conventional coronary artery bypass grafting using bilateral internal thoracic arteries was performed safely via a manubrium-sparing sternotomy in a patient who had undergone total laryngectomy and a permanent tracheostoma. We also discuss the appropriate surgical approach for patients with total laryngectomy and a permanent tracheostoma.Supplementary informationThe online version contains supplementary material available at 10.1007/s12055-021-01309-8.
Project description:An in-vitro study was conducted to investigate the general feasibility of using only one pumping chamber of the SynCardia total artificial heart (TAH) as a replacement of the single ventricle palliated by Fontan circulation. A mock circulation loop was used to mimic a Fontan circulation. The combination of both ventricle sizes (50 and 70 cc) and driver (Freedom Driver and Companion C2 Driver) was investigated. Two clinical relevant scenarios (early Fontan; late Fontan) as derived from literature data were set up in the mock loop. The impact of increased transpulmonary pressure gradient, low atrial pressure, and raised central venous pressure on cardiac output was studied. From a hemodynamic point, the single-chambered TAH performed sufficiently in the setting of the Fontan circulation. Increased transpulmonary pressure gradient, from ideal to pulmonary hypertension, decreased the blood flow in combinations by almost 2 L/min. In the early Fontan scenario, a cardiac output of 3-3.5 L/min was achieved using the 50 cc ventricle, driven by the Companion C2 Driver. Even under pulmonary hypertension, cardiac outputs greater than 4 L/min could be obtained with the 70 cc pump chamber in the late Fontan scenario. In the clinically relevant Fontan scenarios, implementation of the single chambered TAH performed successfully from a hemodynamic point of view. The replacement of the failing univentricular heart by a single chamber of the SynCardia TAH may provide an alternative to a complex biventricular repair procedure or ventricular support in Fontan patients.