Intramyocardial dissecting hematoma: an unusual form of subacute cardiac rupture.

Intramyocardial dissecting hematoma following myocardial infarction is an unusual form of subacute cardiac rupture that tends to develop along naturally occurring dissection planes between the spiral muscles of the ventricle. The diagnosis has commonly been made at surgery, postmortem examination, or by echocardiography. Most are associated with acute transmural inferior infarction. Few patients survive without surgical intervention. Fourteen cases have appeared in the literature. One additional case is described. Ten cases were treated medically with one survivor (10%). Five cases were treated surgically with five survivors. Surgical treatment of intramyocardial dissecting hematoma is preferable to medical treatment. Proper and timely diagnosis and prompt surgical treatment are necessary before complete myocardial rupture ensues. Diagnosis is facilitated through the use of two-dimensional echocardiography. Successful surgical management of this condition requires an appreciation of commonly associated pathoanatomical conditions, and the utilization of appropriate methods of repair in the presence of potential ventricular septal and ventricular free wall rupture.

Modified porous metal-surfaced Björk-Shiley monostrut heart valve. Long-term study in goats without anticoagulation.

To diminish the risk of thrombosis on a mechanical heart valve without anticoagulation, specific areas of the valve ring should be polished, as thrombosis has not been found to start there. By limiting the porous-surfaced area to the groove and the adjacent part of the flange, the thin endothelialized covering of the carbonized suture ring will continue over the groove and top of the flange to the high-flow area. As the high-flow areas that are not completely covered with the neointima, i.e. the struts and the vertical or central portion of the valve ring, are at increased risk of bacterial invasion if their surface is porous, they should be left uncoated and polished.

Optimal microporous surface for endothelialization of metal heart valves in the blood stream.

Optimum surface porosity of a prosthetic heart valve was obtained with use of microspheres less than 40 microns in diameter. A thin and translucent neointima then forms on the valve surface, so thin that its nutrition is supplied by diffusion and thickening will not take place, thereby avoiding interference with the functioning disc. Larger microspheres tend to promote clotting and buildup of fibromyxoid soft tissue, which may cause such interference.

The porous metal-surfaced heart valve. Long-term study without long-term anticoagulation in mitral position in goats.

On review, all thromboembolic complications in mechanical heart valves start from a thrombus lining that covers the suture ring. The thrombus organizes to a fibrous white sheet over the suture ring, which then can protrude out over the polished surface of the valve ring flange. Pieces of the thrombus can be knocked off by the disc and cause emboli. To diminish thromboembolic complications, one must either prevent this thrombus from protruding into the groove between the suture ring and the valve flange or allow the thrombus to be organized as a thin covering with endothelium-like cells as a continuation from the suture ring over the valve flange. This type of covering was obtained during a short period of anticoagulation by applying a microporous surface to the Björk-Shiley Monostrut mitral valve. These valves were implanted in one set of goats and the conventional Björk-Shiley Monostrut mitral valve, with a polished surface, in another set of goats (control group). The two groups were then compared with regard to the incidence of thromboembolic complications encountered during 1 year's follow-up without anticoagulation. The goats were put to death and examination revealed the following observations: In the control group, (1) a varying amount of thrombus formation was found in the groove between the suture ring and the flange in all nine goats and (2) thrombus formation did not start on the polished struts or discs in any of the nine goats. In the group with the microporous Monostrut mitral valve, 19 animals were put to death and examined: (1) The endothelialized covering over the suture ring, thinner when carbon coated, continued over the microporous flange, tapering off in the center of the orifice in all 19 valves on the ventricular side and in 14 of the 19 valves on the atrial side; (2) the center of the orifice and the struts were never completely covered by endothelialized tissue because of high flow; (3) there was an increased incidence of small thrombus formation on the disc-contacting microporous surface of both inflow and outflow struts. Therefore these surfaces should not be coated but left polished.

Albumin prevents erythrocyte crenation in patients undergoing extracorporeal circulation.

Free fatty acid-induced massive erythrocyte crenation has been reported in patients undergoing extracorporeal circulation (EC), suggesting that the crenated cells impair microcirculatory flow and tissue oxygenation during and after the operation. Effect of albumin administration on erythrocyte crenation was examined in 18 patients undergoing coronary bypass operation: 9 patients were given 25 g and another 9 patients were given 50 g of human albumin as a part of the priming solution. Erythrocyte crenation was almost completely prevented in the patients given 50 g albumin. Crenated erythrocytes during EC were 3.6 +/- 2.3% (mean +/- SD) of all erythrocytes and 2.8 +/- 3.7% after EC. This was significantly lower than in patients without albumin administration (63.4 +/- 34.0% during EC and 28.6 +/- 33.3% after EC, n = 20). But the effect was less striking in the patients given 25 g albumin, 32.4 +/- 39.1% during and 28.3 +/- 40.8% after EC. Maintaining an adequate level of plasma albumin is important in preventing erythrocyte crenation during EC, improving microcirculatory flow in patients undergoing open heart surgery.

Erythrocyte crenation induced by free fatty acids in patients undergoing extracorporeal circulation.

Normal erythrocyte morphology is necessary for proper distribution of blood-flow in the microcirculation. Erythrocyte shape was studied in 20 patients undergoing extracorporeal circulation (EC) during coronary bypass surgery. Crenated erythrocytes comprised a mean 64% of all erythrocytes during and 29% after EC. Free fatty acid (FFA) content of the erythrocyte membranes was significantly increased at both times, and FFA content correlated with the proportion of crenated erythrocytes. Washing crenated cells with defatted albumin solution transformed them back to discocytes, simultaneously removing more FFA than that removed from pre-EC discocytes. The plasma FFA to albumin ratio became disproportionately increased during EC; the increased level correlated with severity of erythrocyte crenation. Maintaining a higher level of albumin during EC by adding 50 g human albumin to the extracorporeal system prevented erythrocyte crenation. Entry of plasma FFA not bound to albumin into erythrocyte membranes during EC causes massive erythrocyte crenation.

Exploring the risk of early dismissal following cardiac operations.

The expense for routine postoperative surveillance contributes importantly to the cost of cardiac operations. This study was established to determine the feasibility of earlier dismissals following surgery and whether this would be accompanied by increased risk. All 80 adult cardiac surgery patients undergoing a cardiac operation at one institution during the final quarter of 1983 were included in this prospective study. Patient ages ranged from 34 to 81 years with a mean of 63. Fifty-two per cent were over 65 years old. There were 57 men and 23 women. Of the 80 cardiac operations 85% were coronary artery bypass procedures, with 15% valve operations or other. There was one hospital death. The mean length of postoperative hospitalization was 5 days, and 73% of the patients left the hospital by the 5th postoperative day. Follow-up for 60 days revealed no readmissions nor complications in patients dismissed in 5 days or less. There was one late death presumably from a ventricular arrhythmia in a patient dismissed on the 7th postoperative day. Three point eight per cent (3/79) of the discharged patients were readmitted for varying reasons. The majority of adult cardiac surgery patients can be dismissed safely by the 5th postoperative day. Patients having ventricular arrhythmias or lacking adequate home care are not candidates for early dismissal.

From the spinning disc to the membrane oxygenator for open-heart surgery.

Gibbon's rotating cylinder could not be enlarged to oxygenate an animal larger than a cat. The spinning disc oxygenator, introduced in 1947, had the capacity to perfuse a dog and the potential to increase oxygenation capacity by addition of more discs. When centers began to do three to four open-heart operations per day, the disposable bubble oxygenator was more practical. Bubble size was optimized to decrease the flow of oxygen relative to the blood flow and reduce trauma to blood. The bubble oxygenator is the type most commonly used today. Use of deep hypothermia with whole blood at an esophageal temperature of 10 degrees C was initially complicated by brain damage due to aggregation of white blood corpuscles and platelets. The introduction of hemodilution permitted safe utilization of hypothermic perfusion. Perfusion of infants should not be carried out at hematocrit below 25 ml/100 m. Early membrane oxygenators used nonporous silicone, or modified silicone membranes. High priming volumes, high pressure drop and marginal gas transfer efficiency characterized these devices. Recent advances in membrane technology have spawned a new generation of membrane oxygenators utilizing microporous polypropylene. In these new oxygenators, with either microporous hollow fibers or sheet membrane, the gas transfer characteristics are far superior to those of types produced in the past. The hollow-fiber devices typically have larger surface areas and higher pressure drop than in the new state-of-the-art flat plate models. An evaluation of one of these new-generation membrane oxygenators gave optimal oxygen and carbon dioxide exchange at a gas flow of 1 l/min of 60% oxygen in air at 30 degrees C and 2 l/min of 80% oxygen in air at normal temperature and rewarming for an adult. Today, after almost 40 years of oxygenator development, these new membrane device can offer better platelet preservation and reduced blood trauma as compared with types developed in the past. The new membrane oxygenators are fast becoming the preferred choice for use in infants and in protracted perfusion.

Starch peritonitis and its prevention.

Commercially available surgical gloves contain a derivative of cornstarch and peritonitis induced by particles of starch shed from gloves can be a serious complication of abdominal surgery. Five documented and two suspected cases of this condition are known to have occurred at this institution during a recent 12-month period, when 4,965 intra-abdominal procedures were performed. Clinical features included fever, migratory abdominal pain, and ileus. Treatment with corticosteroids proved effective. Studies of the effectiveness of operating room precautions used to eliminate starch contamination indicated that these precautions do not eliminate the problem completely. Preliminary experience with the use of sodium bicarbonate as a substitute for cornstarch derivatives to "lubricate" surgical gloves has proved promising in eliminating the hazard of starch peritonitis.