Efficacy of Thoratec Implantable Ventricular Assist Devices Compared
Efficacy of Thoratec Implantable Ventricular Assist Devices Compared to Syncardia Total Artificial Hearts as Bridge-to-Transplantation Therapy in Adults with Biventricular Heart Failure Alexandria Davenport MPH (c); MMS (c) Faculty Advisor: Renee Langstaff, MSPAS, PA-C Department of Medical Science Discussion Abstract Results Systolic heart failure is a chronic condition in which there is a decrease in the heart’s ability to pump blood to the body. While there are several treatments for the symptoms of heart failure, the only curative treatment for most causes of chronic heart failure is a heart transplant. Mechanical circulatory support has been used to increase patient survival to transplantation. Therefore, this review compares the use of Syncardia’s total artificial heart to Thoratec’s implantable ventricular assist device (I) in waitlist survival (O) in adult patients in biventricular systolic heart failure (P). Torregrossa et al. examined the use of the TAH specifically for longer than one year. The authors found that 72% of patients were successfully transplanted after a year or more with the Syn. Cardia TAH. Similarly, Slaughter et al. was chosen for this review partially because it indicated the long-term support ability of the Thoratec IVAD, in which the mean duration of support with successful transplant of 108 days with a maximum of 597 days. In total, six of the seven total studies showed survival to successful transplantation in the TAH or the IVAD after a year on mechanical circulatory support. Kirsch et al. , Levin et al. , and Cheng et al. directly compared waitlist survival between Bi. VADs, and none of the authors found a significant difference between Bi. VAD and TAH patients. However, Kirsch et al. found TAH patients had significantly lower rates of ischemic stroke and a trend toward improved survival for patients that required 90 days or more on support. Cheng et al. found that, while waitlist survival did not significantly differ between TAH and Bi. VAD patients, in terms of waitlist complications, the rate of renal failure was higher in the TAH group and the rate of infection was higher in the Bi. VAD group. Introduction Overview Defined as a decrease in the heart’s ability to pump The most common cause of systolic heart failure in the US is ischemic cardiomyopathy from a previous myocardial infarction (heart attack) In 2016, approximately 6. 2 million Americans have been diagnosed with heart failure In 2012, the cost of heart failure on the health care system was $30. 7 billion Symptoms Dyspnea, fatigue, exercise intolerance, fluid retention (i. e. edema, ascites, nocturia) Treatment Patients with symptoms refractory to medication and the ICDs are candidates for ventricular assist devices (VADs) and/or transplantation Methods Literature Search Performed in November 2018 using Google scholar Search terms: “‘biventricular’ thoratec ‘IVAD’” and “syncardia” Other methods employed: articles that cited “Results of a multicenter clinical trial with the Thoratec Implantable Ventricular Assist Device” Exclusion criteria: 1. Studies that focused on pediatric populations. 2. Case studies 3. Studies focusing only on left or right heart failure. Table 1. Comparison of Results Study Configuration Slaughter et al Torregrosssa et al Kirsch et al Cheng et al Levin et al Shah et al Fitzpatrick et al Survival to Adverse Reactions Transplantation 100% Implantable Bi. VAD S 100% TAH S 67% Paracorporeal Bi. VAD NS 25% TAH 12% Implantable Bi. VAD 37% TAH NS 63% Bi. VAD 57. 7% TAH NS 9. 4% Continuous Flow Bi. VAD 32. 9% Pulsatile Flow Bi. VAD 100% TAH S 71. 7% Planned Bi. VADs S 28. 3% Delayed Bi. VADs Key: S=Significant; NS=Not significant; N/A=Not applicable S S NS S N/A Of the three studies (Kirsch et al. , Levin et al. , and Cheng et al. ) that directly compared waitlist survival between Bi. VADs, none of the authors found a significant difference between Bi. VAD and TAH patients. Six of the seven total studies showed survival to successful transplantation in the TAH or the IVAD after a year on mechanical circulatory support (51. 7% of patients on the UNOS registry for heart transplants in 2017 waited up to a year for a transplant). Torregrossa et al. examined the use of the TAH specifically for longer than one year, finding that 72% of patients were successfully transplanted after a year or more with the Syn. Cardia TAH. Slaughter et al. found long-term support ability of the Thoratec IVAD, in which the mean duration of support with successful transplant of 108 days with a maximum of 597 days. Limitations: 6/7 studies were retrospective out of multiple healthcare centers There was no protocol: device selection was based on clinician discretion Conclusion Results show that there is not a significant difference in waitlist survival between the IVAD and the TAH or as biventricular assist devices as a whole and the TAH. There is not enough evidence at this time to show that one device is better than another. The IVAD and the TAH each have their advantages and disadvantages in terms of size, portability, complication rates, and patient tolerance. Results of these studies do not justify a standardization of mechanical circulatory support treatment and healthcare providers should continue to research and inform patients of all the configurations available to them. References: 1. Bashore TM, Granger CB, Jackson KP, Patel MR. Heart Disease. In: Papadakis MA, Mc. Phee SJ, Rabow MW. eds. Current Medical Diagnosis & Treatment 2019 New York, NY: Mc. Graw-Hill. http: //accessmedicine. mhmedical. com/content. aspx? bookid=2449§ionid=194435482 2. Colvin M, Smith JM, Hadley N, et al. OPTN/SRTR 2017 Annual Data Report: Heart. American Journal of Transplantation. 2019; 19: 323 -403. 3. Organ Procurement and Transplantation Network. Waitlist: Waiting Time by Waiting List Status. https: //optn. transplant. hrsa. gov/data/view-data-reports/build-advanced/
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