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Mechanical Effects of Cardiovascular Drugs and Devices
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
The second category of short-term blood-contacting devices is external circuits through which blood is pumped and oxygenated. These include cardiopulmonary bypass (CPB), used during open heart surgery, and extracorporeal membrane oxygenation (ECMO), which provides longer-term support when evaluating treatment options for cardiopulmonary dysfunction. Cardiopulmonary bypass was developed in 1953 by Dr. John Gibbons at the Mayo Clinic to support the open-heart surgery needed for heart transplantation. In CPB, the patient’s heart is arrested and blood is diverted through an external circuit for gas exchange before being returned to the body. This provides a static bloodless field for the surgeon to repair the heart chamber or valves, replace valves or blood vessels, implant a left ventricular assist device (LVAD), remove clots from the pulmonary artery, and transplant a heart. The circuit is connected to the circulation under general anesthesia, with aortic cannulation for return of oxygenated blood and right atrial cannulation for gravity-assisted drainage of deoxygenated blood into the circuit. A perfusionist monitors and regulates blood flow and blood oxygenation to optimize tissue perfusion and protection. Most procedures strive to limit the time on CPB to 1 hour or less.
Big Data and Transcriptomics
Published in Shampa Sen, Leonid Datta, Sayak Mitra, Machine Learning and IoT, 2018
Sudharsana Sundarrajan, Sajitha Lulu, Mohanapriya Arumugam
Various applications of microarray technology have been utilized in the area of cardiomyopathy. Some studies involved comparisons of failing and nonfailing heart, before and after left ventricular assist device (LVAD) implantation, and dilated and hypertrophic cardiomyopathy. The microarray analysis of failing and nonfailing hearts provides therapeutic insights. The gene expression profile comparison identified that the genes involved in fatty acid metabolism were up-regulated and genes involved in glucose metabolism were down-regulated in failing hearts. These results provide an insight into drugs prescribed to shift fatty acid to glucose metabolism. In a supervised analysis of the gene expression of the dataset of the patients with heart failure, the investigators observed changes in the pattern of gene expression at different clinical stages.12–13 In the study conducted by Steenman et al, on failing and non failing hearts, a distinct cluster of patients emerged during unsupervised analysis, who require the highest medical urgency while awaiting cardiac transplantation.14
Corporate Entrepreneurship
Published in Szycher Michael, Szycher’s Practical Handbook of Entrepreneurship and Innovation, 2018
For example, in August 1983, Thermedics (the first of Thermo’s IPO spin-outs) raised a total of $6 million. At the time, Thermedics had several research contracts from the National Heart, Blood, and Lung Institute (NHLBI) to develop a surgically implantable left ventricular assist device (artificial heart) for patients in irreversible congestive heart failure. However, NHLBI funding was decreasing and the future looked bleak. Indeed, Thermedics’ offering prospectus clearly warned of “substantial operating losses” to come. Nonetheless, Thermo retained 4.2 million shares (86.6% of the total share issuance) of Thermedics, whose post-IPO market value was an astounding $40 million.
Pediatric ventricular assist devices: what are the key considerations and requirements?
Published in Expert Review of Medical Devices, 2020
Roland Hetzer, Mariano Francisco del Maria Javier, Eva Maria Javier Delmo
While heart transplantation has gained recognition as the gold standard therapy for advanced heart failure, the scarcity of donor organs has become an important concern. The evolution of surgical alternatives such as ventricular assist devices (VADs) has enabled recovery of the myocardium and ensured patient survival until heart transplantation becomes possible. While several device options are available for the adult population with heart failure, many of these have been unavailable for children. VADs for pediatric patients continue to lag in development. The main cause for limited device availability for pediatric applications is clear – small numbers of affected children make it difficult for manufacturers to justify the expense for development and legalization and other resources required for the limited pediatric market. Likewise, there is no heart pump with the design innovation to support dysfunctional states of heart failure and the anatomic heterogeneity of cardiac defects in pediatric patients.
In Vitro models for thrombogenicity testing of blood-recirculating medical devices
Published in Expert Review of Medical Devices, 2019
Mechanical Circulatory Support (MCS) is commonly used in patients with advanced heart failure. Small, continuous, flow pumps, such as ventricular assist devices (VADs) have replaced older, pulsatile pumps to improve cardiac ventricular function in the left (LVAD), right (RVAD) or both ventricles (biVAD). As VAD technology has evolved, VADs are now able to provide long-term therapies for transplant-ineligible patients [5]. A review of in vitro testing of VADs shows that most thrombosis testing studies rely on hemolysis, leaving most of the tests called for in ISO 10993–4 to in vivo testing setups. This may be due to the fact that promising in vitro hemolysis data does not always correlate with acceptable hemolysis values in vivo as demonstrated by the PediaFlow 1 VAD (HeartWare International, Inc, Framingham, Mass) [6]. While total artificial hearts (TAH) have been used as a bridge to transplantation therapies since 1969, development on total artificial hearts was slowed by complications such as hemolysis and thrombosis [7]. Recently, the temporary total artificial heart (t-TAH) and C2 Driver System (Syncardia Systems Inc, Tucson, AZ), which is designed as a bridge to transplantation therapy for patients with biventricular failure who are not candidates for LVAD placement was developed [8]. In August 2018, the FDA flagged this device in a letter to health-care providers for higher mortality and stroke incidents in clinical application compared to its predecessor, the t-TAH with Circulatory Support System (CSS) console.