Biomedical subjects

Michael A Acker

Publications and source records attributed to Michael A Acker.

6 recordsLinked to original sources

PubMed2002

Ventricular constraint using the acorn cardiac support device reduces myocardial akinetic area in an ovine model of acute infarction.

BACKGROUND: Left ventricular remodeling secondary to acute myocardial infarction (AMI) is characterized by ventricular dilatation and regional akinesis. In this study, we investigated the effect of passive constraint on akinetic area development. METHODS AND RESULTS: The effect of passive constraint on akinetic area was investigated in 10 sheep using tissue-tagging magnetic resonance imaging (MRI). A baseline MRI study was followed by the creation of an anterior infarct. After 1 week, the animals received a second MRI study. A cardiac support device (CSD) was then placed over the epicardium in 5 sheep whereas the remaining animals served as controls. A terminal study was performed at the 2-month postinfarct in both groups. The akinetic area at 1-week postinfarct was similar in both groups. At the terminal time-point, the akinetic area in the control group was similar to the 1-week time-point whereas in the CSD group, the area of akinesis decreased (P=0.001). A comparison of the 2 groups at the terminal time-point demonstrates a significantly diminished area of akinesis in the CSD group (P=0.004). The relative area of akinesis followed a similar pattern. End-systolic and end-diastolic wall thickness was significantly greater in the CSD group at terminal (P=0.001). In addition, the minimum wall thickness was greater in the CSD group compared with the controls (P=0.04). CONCLUSIONS: Passive constraint reduced akinetic area development secondary to AMI. The attenuation of regional wall stress may prevent the incorporation of the border zone into the infarct, decreasing infarct size and providing a promising new therapy for patients after an AMI.

Animals↗

PubMed2002

CD3 monitoring of antithymocyte globulin therapy in thoracic organ transplantation.

BACKGROUND: Antithymocyte globulin is frequently used as a component of induction therapy in thoracic organ transplantation. This study evaluates the utility of monitoring peripheral CD3 lymphocytes to rationally adjust antithymocyte globulin therapy in this patient population. METHODS: A total of 17 heart and 19 lung transplant recipients received antithymocyte globulin (ATGAM or thymoglobulin) as induction therapy or to treat steroid-resistant acute or chronic rejection. Absolute CD3 counts were maintained between 50 and 100 cells/microl. RESULTS: With CD3 monitoring, the doses of antithymocyte globulin were reduced from 10-15 mg/kg to 1-5 mg/kg during the course of therapy. The total amount of antithymocyte globulin given to each CD3 monitored patient was reduced by 48%. Dose reduction did not alter the number of acute rejection or infectious episodes, and hematological side effects were infrequent. CONCLUSION: CD3 monitoring of antithymocyte globulin therapy in thoracic organ recipients reduced the amount of drug received by each patient, while maintaining CD3 counts less than 100 cells/microl.

Acute Disease↗

PubMed2002

Left ventricular assist device for right side assistance in patients with transposition.

Right (systemic) ventricular dysfunction is well described after Senning operations for transposition of the great arteries, and patients with congenitally corrected transposition of the great arteries. Transplantation remains the only definitive therapy for refractory heart failure, however patients may deteriorate clinically prior to the availability of a donor heart. This report details the implantation of a TCI Heartmate (Thoratec Corp., Pleaston, CA) as a morphologic right ventricular assist device to bridge these patients to transplantation.

Adolescent↗

PubMed2002

Successful explantation of a ventricular assist device following fulminant influenza type A-associated myocarditis.

We report a case of fulminant myocarditis associated with refractory ventricular fibrillation following influenza A infection. Histologic examination was consistent with myocarditis and serology confirmed the viral etiology. The patient was supported with biventricular assist devices for 20 days during which her refractory ventricular fibrillation resolved spontaneously. This is the first documented case of resolution of prolonged ventricular fibrillation while on a ventricular assist device. This case suggests those patients with fulminant viral myocarditis and refractory ventricular arrhythmias may be supported successfully with ventricular assist devices until myocardial recovery takes place.

Adult↗

PubMed2002

Surgical management of heart failure: an overview.

Cardiac transplantation remains the gold standard of surgical therapies for advanced and end-stage heart failure. However, this very limited option trades one disease for another and can benefit only a small minority of patients. Heart failure is currently considered secondary to a structural increase in ventricular chamber volume or remodeling. Surgical therapies formerly contraindicated for the failing heart, as well as new therapies, can successfully affect ventricular remodeling and improve cardiac function. Surgical revascularization for patients with ejection fractions <20% is becoming common. Mitral valve repair is being explored, with surprisingly low operative mortality and encouraging intermediate results. Direct surgical approaches to restoring normal geometry and size to failing hearts, such as left ventricular reduction (Batista procedure), endoventricular patch plasty (Dor procedure), cardiomyoplasty, and prosthetic external constraints are under clinical investigation. Developments in mechanical assist therapy and a new generation of implantable intracorporeal assist devices are also discussed.

Animals↗

PubMed2002

Propofol.

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Adolescent↗