1. Surgical Implantation of the Acorn Cardiac Support Device
Mehmet C. Oz 
Operative Techniques in Thoracic and Cardiovascular Surgery 
Volume 7, Issue 2, Pages (May 2002)
DOI: /otct
Copyright © 2002 Elsevier Inc. Terms and Conditions

2. Fig I
Cardiac support device structure. (Top) Actual size of 5-mm section. (Bottom) Polyester weave that reduces stretching in transverse dimension more than in longitudinal axis (30X magnification).
Operative Techniques in Thoracic and Cardiovascular Surgery 2002 7, DOI: ( /otct )
Copyright © 2002 Elsevier Inc. Terms and Conditions

3. 1
If the CSD is used as sole therapy, off-pump placement is preferred. The device can also be implanted in conjunction with other reparative operations that mandate cardiopulmonary bypass including coronary artery bypass surgery. In these cases, device implant should be started with the patient on pump support to facilitate placement of the posterior atrioventricular (AV) groove sutures.
After sternotomy, the pericardium is opened and the diameter of the left ventricle at the midpapillary muscle level is measured using transeophageal echocardiography (TEE). The heart is prepared for device placement by creating a pericardial cradle. We generally use a technique advocated by many off-pump CABG surgeons. The right-sided pericardium is excised inferiorly along the diaphragm. The right side of the pericardium is left flaccid while the left-side pericardial edge is retracted up toward the sternum to begin the rotation of the heart toward the right. Two 2-0 Teflon-coated Dacron sutures are placed in the pericardium adjacent to the left superior and inferior pulmonary veins. As these sutures are retracted toward the sternum, the cardiac apex is rotated toward the patient's right chest. The patient is rotated to the right to facilitate positioning of the heart and exposure of the posterior AV groove. The anesthesia team monitors and adjusts the patient's volume load to ensure adequate hemodynamics and stable heart size during the implant procedure. (A) Either before or after completion of the pericardial cradle, a measuring tape or cord is placed around the heart at the base to approximate the heart's circumference. (B) The same tool can also be used to estimate the length of the heart from base to apex anteriorly. These two measurements are used to select the appropriate-sized CSD according to the manufacturer's sizing chart.
Operative Techniques in Thoracic and Cardiovascular Surgery 2002 7, DOI: ( /otct )
Copyright © 2002 Elsevier Inc. Terms and Conditions

4. 2
Once chosen, the CSD is positioned around the ventricles, with particular care taken to ensure that the hemline lies over or just below the AV groove. A series of 4-0 polypropylene sutures are used to secure the material in place (A). We generally use four sutures posteriorly located at the left atrial appendage, medial to the inferior vena cava, and in between these two sites over the coronary sinus. Next, the device is wrapped over the apex and pulled to the AV groove anteriorly (B). Additional 4-0 polypropylene sutures are placed in the AV fat pad on the left lateral aspect of the heart as the mesh is pulled tautly into apposition with the heart. In a similar fashion, sutures secure the mesh medially above the right coronary artery. Care should be taken to avoid injuring the epicardial vessels. Because only the epicardium is needed to provide adequate strength to hold the mesh in place, deep sutures are discouraged. Excess fabric is accumulated anteriorly in preparation for final fitting of the device.
The device is adjusted to fit snugly around the ventricles and cause a slight reduction in circumference of heart, thus ensuring that the CSD relieves a portion of mechanical stress in the ventricular wall (C). We seek to reduce the diameter of the heart (as measured by TEE) by 5%, but vigorously avoid any reduction greater than 10% to minimize the risk of any adverse events related to device fit. A specialized clamp is used to secure the mesh as it is pulled taut over the right ventricle (B, C, D). Once TEE confirms the desired degree of reduction, excess material above the clamp is excised and the mesh is resutured using 4-0 polypropylene (D, E, F). The clamp is removed, the new anterior seam is reinforced, and the mesh is secured circumferentially with placement of the final anterior stay sutures.
Operative Techniques in Thoracic and Cardiovascular Surgery 2002 7, DOI: ( /otct )
Copyright © 2002 Elsevier Inc. Terms and Conditions