Biomedical subjects

John Elefteriades

Publications and source records attributed to John Elefteriades.

5 recordsLinked to original sources

PubMed2006

Mechanical reliability of the Jarvik 2000 Heart.

BACKGROUND: Device failure is a limitation of permanent mechanical circulatory support. We studied the mechanical reliability of the Jarvik 2000 Heart, an axial flow pump with ceramic bearings designed to provide more than 10 years' durability. METHODS: The Jarvik 2000 Heart was implanted in 102 patients between April 2000 and December 2004. Eighty-three pumps with an abdominal driveline were implanted as a bridge-to-transplantation, and 19 with postauricular power supply as lifetime therapy. Eighteen pumps were recovered intact after clinical use and run continuously on the bench to further assess durability. RESULTS: No implantable component failure occurred either in patients or during bench testing. The cumulative pump run-time was 110 years: 59 years overall in vivo and 51 years in vitro. The mean support time for bridge-to-transplant recipients was 159 days, and for discharged lifetime-therapy recipients 551 days. Six recipients were supported moer than 2 years, with the longest ongoing approaching 5 years. External cables caused three system failures, with a 95% freedom from system failure at 4 years. Device malfunctions, related to external cables (9) and lack of a backup battery (1), caused no adverse consequences. Before introduction of noncorrosive, gold-plated stainless steel connectors, corrosion was observed on three connectors to the retroauricular power supply. CONCLUSIONS: The Jarvik 2000 Heart has had no implantable component failure. Meaningful durability data and failure mode can only be established by real-time testing in patients. The reliability and dependability of this device, in addition to the exchangeability of external components, give promise for long-term circulatory support in critically ill heart failure patients.

Equipment Failure Analysis↗

PubMed2006

Aprotinin use in thoracic aortic surgery: safety and outcomes.

OBJECTIVES: Previous studies of aprotinin use in thoracic aortic surgery, limited in size and design, reported minimal information regarding outcomes other than blood loss and transfusion. The evaluation of impact of aprotinin on surgical outcomes in a large sample is needed. METHODS: Patients at Yale New Haven Hospital undergoing thoracic aortic surgery (aneurysm repair, dissections, penetrating ulcers, intramural hematomas) between 1995 and 2003 were considered for inclusion. Each patient receiving aprotinin was matched to a control per preoperative profile (age, gender, urgency of surgery, dissection/location of aortic disease). Data (surgical specifics, demographic variables, comorbidities, disease location-related variables, preoperative medications, intraoperative medications, surgical/operative data) were abstracted from the records of successfully matched aprotinin-treated patients and controls (n = 168). Comparison and determination of success of matching were performed using bivariate analyses. Outcome variables were compared using statistical tests for paired data. Supplementary unpaired and regression analyses were also performed. RESULTS: Baseline demographics of groups were similar, although controls had reduced history of aortic disease, but greater intraoperative use of lysine analogs (P < .05). Aprotinin significantly reduced platelet transfusion (P < .05). Paired bivariate analyses showed a tendency toward reduced ventilation time, pulmonary complications, and permanent arrhythmias (P < .05) associated with aprotinin. Supplementary analyses were supportive only for pulmonary complications and permanent arrhythmias. CONCLUSIONS: The current evaluation substantiates previous reports that aprotinin may be safe to use and likely to improve some outcomes of thoracic aortic surgery. However, further studies for rare safety and efficacy end points are warranted.

Aorta, Thoracic↗

PubMed2005

Ascending thoracic aneurysms are associated with decreased systemic atherosclerosis.

STUDY OBJECTIVES: We noted clinically that patients with aortic root aneurysms and dissections seemed to have little systemic atherosclerosis. It is our objective to determine whether there is a negative association between ascending thoracic aneurysms and systemic atherosclerosis. DESIGN: Atherosclerosis was quantified by evaluating non-contrast CT images of the chest and scoring the degree of calcifications as a marker for atherosclerosis in the coronary arteries and aorta. PATIENTS: The degree of calcification was compared in 64 patients with aortic root aneurysm (annuloaortic ectasia, 31 patients; type A dissection, 33 patients) vs 86 control subjects. Multivariable analysis was applied to test for an association between aortic root aneurysms and systemic calcification independent of risk factors for atherosclerosis. RESULTS: Multivariable analysis revealed that patients with ascending aortic aneurysms of the annuloaortic ectasia type and patients with type A dissections had significantly lower overall calcification scores in their arterial vessels compared to patients in the control group (p = 0.03 and p < 0.0001, respectively). These results were independent of all other risk factors for atherosclerosis. Smoking, dyslipidemia, diabetes, and age were all found to increase the degree of atherosclerosis (p < 0.01 to 0.05). CONCLUSIONS: Aortic root pathology (annuloaortic ectasia or type A dissection) is associated with decreased systemic atherosclerosis. It is possible that a mechanism exists whereby the same genetic mutations predisposing patients to ascending aortic aneurysms also exert a protective effect against systemic atherosclerosis.

Aged↗

PubMed2003

Novel technique for isolated accessory right heart transplantation for congenital heart disease.

BACKGROUND: Our prior laboratory work has permitted adding a whole donor heart to a preserved recipient right heart, producing a heart-and-a-half preparation able to cope with pulmonary hypertension in the recipient. The experiments in the present study explore the feasibility of the converse operation: adding an isolated donor right heart to an entire preserved heart. METHODS: Eight adult mongrel dogs (4 donors and 4 recipients) were used in 4 transplant operations performed through a right thoracotomy without cardiopulmonary bypass (using side-biting control of recipient vessels). The donor heart underwent resection of the left atrium and left ventricle, leaving an isolated donor right heart. Blood supply to the donor right ventricle was preserved from the donor ascending aorta. Through a right thoracotomy, the donor right heart was transplanted in parallel to the native right heart of the recipient by using the following anastomoses: (1) donor superior vena cava to recipient superior vena cava (end-to-side anastomosis); (2) donor pulmonary artery to recipient pulmonary artery (end-to-side anastomosis); (3) donor ascending aorta to recipient aorta (through a great vessel [end-to-end anastomosis] to provide arterial inflow to donor coronary arteries). Animals were euthanized within 1 hour after completion of transplantation. RESULTS: Isolation of the right ventricle by excision of the left chambers was technically feasible. Transplantation without cardiopulmonary bypass was feasible in all cases. The isolated right heart beat well after transplantation in all animals, demonstrating sinus rhythm. Three of 4 animals were able to sustain good hemodynamics on support with epinephrine. Bleeding from the septum or aortic valve of the donor (now open to the pericardial space) was not problematic. Mean arterial pressure was 85 mm Hg (mean) at a right atrial pressure of 6 mm Hg (mean). In 2 animals the recipient superior vena cava was ligated to obligate upper body flow to pass through the accessory ventricle; hemodynamics were preserved under these circumstances. CONCLUSION: Transplantation of an isolated right heart is feasible. Such a technique has potential as a novel therapeutic alternative for obstructive or hypoplastic lesions of the right heart in human children.

Anastomosis, Surgical↗

PubMed2002

Coronary bypass in left heart failure.

Clinical experience is accumulating that coronary artery bypass grafting is of great benefit in patients with advanced ischemic cardiomyopathy. At Yale University, we have analyzed short- and long-term results in 188 consecutive patients with an ejection fraction (EF) of 30% or less undergoing coronary artery bypass grafting by a single surgeon. This experience permits the following conclusions: (1) Surgery can be performed safely (mortality 2.8% in elective patients); (2) Major improvement in left ventricular (LV) function is objectively demonstrable (EF change from 23.3% to 33.2%); (3) Symptomatic improvement is noted by patients (NYHA class change from 3.1 to 1.4); and (4) Good long-term survival is realized, relative to expectations with medical management alone (88%, 77%, and 60% at 1, 3, and 5 years). If coronary artery disease is severe and proximally situated and there are adequate target arteries, we do not deny patients surgery based on EF or LV size criteria, nor do we require objective demonstration of reversible ischemia. In fact, hearts in the largest size range (left ventricular end-systolic volume index > 100 mL) actually showed beneficial reverse remodeling subsequent to coronary artery bypass grafting. Surgical revascularization is recommended strongly for patients with advanced ischemic cardiomyopathy. Results rival those of transplantation.

Cardiopulmonary Bypass↗