Joseph D. Marco

Autologous Platelet-Rich Plasma in Cardiac Surgery: Effect on Intraoperative and Postoperative Transfusion Requirements

The Southern Arizona Red Cross Blood program, in conjunction with participating hospitals and cardiac surgeons, evaluated the effect of a program to harvest autologous platelet-rich plasma (PRP) from patients immediately prior to undergoing cardiopulmonary bypass surgery. The PRP was transfused back to the patient after heparin neutralization was achieved at the completion of cardiopulmonary bypass. The effect of this autologous PRP product on homologous plasma and platelet usage was examined. The study demonstrates a significant decrease in homologous plasma and platelet usage when autologous PRP is used in cardiac surgery.

Topical Cardiac Hypothermia and Phrenic Nerve Injury

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

Determinants of homologous blood usage utilizing autologous platelet-rich plasma in cardiac operations.

The present study evaluated (1) the influence of the collection of autologous platelet-rich plasma intraoperatively in addition to intraoperative autotransfusion on homologous blood usage and bleeding in cardiac operations; (2) the influence of age, sex, body surface area, type of operation, and reoperations on homologous blood usage and bleeding in cardiac operations utilizing intraoperative autotransfusion and autologous platelet-rich plasma collected intraoperatively; and (3) the influence of the preoperative administration of aspirin, Persantine (dipyridamole), heparin sodium, thrombolytic agents, Coumadin (crystalline warfarin sodium), and nonsteroid, antiinflammatory drugs on homologous blood usage and bleeding in cardiac operations utilizing intraoperative autotransfusion and autologous platelet-rich plasma collected intraoperatively. The results demonstrated a decrease in homologous blood use and bleeding when autologous platelet-rich plasma is collected in addition to the use of intraoperative autotransfusion. All of the patient and procedural variables influenced homologous blood usage and bleeding to some extent. Only the thrombolytic agents affected blood usage by increasing homologous plasma usage. All other drugs evaluated did not influence blood utilization or the amount of bleeding intraoperatively or postoperatively.

Coronary Venous Arterialization: Acute Hemodynamic, Metabolic, and Chronic Anatomical Observations

Nine dogs that had anastomosis of the internal mammary artery (IMA) to the left anterior descending coronary vein (LADV) were studied acutely on right-heart bypass. Occlusion of the left anterior descending coronary artery (LADA) and LADV without venous arterialization resulted in a significant decline in stroke work, total coronary flow, and myocardial oxygen uptake; with reactive hyperemia an increase in lactate and pyruvate consumption resulted. Occlusion of the LADA and LADV with VA did not change these variables greatly, except for a marked increase in total coronary flow with reactive hyperemia. Chronic venous arterialization in 14 dogs was associated with a 14% mortality, while 10 controls had a 40% mortality. Dogs were killed at six weeks, and prior angiography in 9 showed patency of the IMA to the heart without filling of cardiac veins. All dogs had infarcts in the distribution of the LADA; these infarcts were smaller in dogs with venous arterialization. The anastomoses were obliterated by mature or maturing fibrous tissue, with alteration of the vein so that it was frequently not discernible, while the IMA was well preserved. Distal veins had foci of intimal proliferation, subintimal fibrosis, and medial hypertrophy. Although venous arterialzaiton provides protection for the acutely ischemic myocardium, this effect does not persist, perhaps because of anastomotic occlusion due to fibrous proliferation.

Intraaortic Balloon Assistance

Intraaortic balloon (IAB) assistance in 64 patients over 2 1/2 years has resulted in a survival rate of 11% (1 patient) when used alone but 47% when utilized in patients treated surgically (long-term survival, 38% [21 patients]). Patients undergoing coronary artery bypass grafting or aortic valve replacement have a long-term survival of 50% (8 and 9 patients, respectively). The required duration of IAB support has a bearing on the clinical result. Complications have been minimal. Though it was originally developed to assist in the nonoperative management of complications of ischemic heart disease, IAB assistance offers significant promise as an adjuvant to operative therapy for both ischemic and valvular heart disease.

Pulmonary and left atrial hemodynamics in mitral stenosis

A laboratory model has been utilized to evaluate left atrial and pulmoanry hemodynamics while comparing atria of three different compliances, five valve orifices, four pulmonary complicances, two venous pressures, and a predetermined pulmonary vascular resistance. The data demonstrate significant relationships between these variables and cardiac output, pulmonary artery pressure, and left atrial pressure and between the variables themselves. The complexity of these interrelationships is consistent with the lack of simple linear relations between current clinical measurements and emphasizes the need for measurements of compliance if the hemodynamic consequences of mitral stenosis are to be better understood.

A Servocontrolled Atrial-Aortic Assist Device: Experimental Findings and Clinical Experience

A servocontrol system was developed to regulate a single roller pump left atrial-aortic (La-A) assist device. Responsiveness of the servomechanism to blood volume changes, myocardial damage, and mitral regurgitation was evaluated in 5 sheep and 6 dogs. Myocardial damage was induced by occlusion of coronary arteries. and the hemodynamic effects of La-A assistance were evaluated. While La-A assistance reduced left atrial pressures to low levels, the left ventricular end-diastolic pressure remained elevated in the severely damaged heart. LaA-assistance was used in 3 patients. Two were weaned from cardiopulmonary bypass after failure of intraaortic balloon counterpulsation, and 1 is a long-term survivor. The third was supported for 48 hours after attempt repair of complex congenital heart disease. The servocontrol device added to the safety of prolonged La-A assistance. This mode of assistance should be considered when intraaortic balloon counterpulsation has failed.

In Favor of the Y-Graft for Aortocoronary Bypass

The technique of multiple coronary artery bypass grafting has included separate conduits, snake grafts, and Y-grafts. Against the Y-graft have been reports of lesser patency and several theoretical objections. The theory is discussed and a laboratory model presented which demonstrates a flow difference of 2 ml/5 sec or less between Y-grafts and single grafts. In conjunction with this, 171 patients having aortocoronary bypass were analyzed and showed a combined one-year graft patency of 77% with no significant difference between single grafts and Y-grafts. It is concluded that the technical simplicity of Y-grafts is advantageous and that, if the operation is performed within the guidelines set forth, revascularization with Y-grafts is an acceptable method.

Intracardiac Repair after Previous Pulmonary Artery Banding

Surgical treatment of infants with a large ventricular septal defect (VSD) unresponsive to medical therapy is sometimes indicated. Pulmonary artery banding originally described by Muller in 19521 has proven to be an adequate operation for controlling high pulmonary flow. In the past, a two staged procedure consisting of pulmonary artery banding followed by debanding and VSD closure has been used.2 More recently primary closure during infancy using deep hypothermia has been advocated.3 We have reviewed the results of debanding and VSD closure in an attempt to set a standard with which to compare primary closure which we now use.