Centrifugal pump failures.

Centrifugal pumps will not pass gross quantities of gaseous emboli due to the nonocclusive nature of the pump. However, retrograde flow can occur under circumstances that include: product malfunctions, low flows, and human errors. Negative pressure created by falling arterial perfusate can draw air into the cannula. Food and Drug Administration (FDA) records about centrifugal pump malfunctions were obtained. Out of 350,000 cases completed with centrifugal pumps over a 23 month period, the FDA received reports of 68 malfunctions, 22 electrical burning smells, and three speed surges, yielding a failure rate of 1 in 3,763 cases. FDA records revealed five death reports and three serious injury reports. A survey was sent to 2,424 Society of Thoracic Surgeons' members to obtain more information; 285 who use centrifugal pumps responded. Sixty surgeons (21%) reported 108 malfunctions, including 46 complete pump failures. Fifty-one of 243 surgeons (21%) who use centrifugal pumps for bypass reported that perfusionists have forgotten to clamp the pump line, resulting in backflow. We conclude centrifugal pumps are generally safe, but malfunctions, low flows, and human errors can lead to retrograde flow and occasionally air embolization. There are valves that can be added to the bypass circuitry to prevent this risk.

Results of the unidirectional Centri-Safe arterial valve for prevention of retrograde flow during cardiopulmonary bypass.

Retrograde blood from the aortic cannula into the cardiopulmonary circuit may lead to aortic air emboli when nonocclusive centrifugal pumps are used. The authors tested a nonregurgitant, unidirectional valve containing a Teflon ball occluder to prevent backflow. In vitro measurements of leakage rate, forward flow pressure drop, burst strength, and hemolysis levels along with animal (n = 12) and human (n = 12) in vivo hematologic and hemolysis levels were measured. Data were analyzed by paired and unpaired Student's t-test. Pressure drop differences at flows of 5 l/min were 7.3 +/- 0.3 mmHg before and 7.6 +/- 0.1 mmHg after 10,800 cycles of pulsatile pumping. (P = NS). Leakage rate during this period at pressures of 100 mmHg was not significant. Volume required to close the Teflon ball was less than 1 ml. Hemolysis analysis done in vitro and in vivo in control (no valve) and experimental (valve) groups used hemoglobin, hematocrit, platelets, plasma free hemoglobin, and lactic dehydrogenase as hemolysis indices. There were no statistical differences. The authors conclude that the CentriSafe valve (Cardiac Systems, Inc., Conshohocken, PA) is safe and prevents fatal backflow and air emboli. The valve is nonthrombotic in anticoagulated blood, can be opened and closed thousands of times, and has a burst strength equal to or greater than other components in the perfusion setup.

New technique for coronary sinus cannulation using a fiberoptic stylet.

Fluoroscopy, echocardiography, blind digital approach, and direct visual insertion have been used for retrograde cannulation of the coronary sinus. We cannulate the coronary sinus by transillumination using a standard flexible retroplegia cannula with a reusable fiberoptic stylet designed by our open heart program. An attachable light source illuminates the tip, which is guided into the coronary sinus ostium. We have used the technique in 16 patients who could not be cannulated with the blind digital method.

Management of patent saphenous vein grafts during reoperative coronary artery bypass grafting.

A patient was referred for coronary artery bypass reoperation. After a left internal mammary artery was grafted to the left anterior descending coronary artery, the diseased but patent old saphenous vein graft was ligated. This resulted in severe myocardial failure, which was corrected only after restoration of flow through the old vein graft. We suggest the decision to ligate or replace an old vein graft should be individualized to avoid the risk of myocardial ischemia.

In vitro melanoma cell growth after preenucleation radiation therapy.

The in vitro efficacy of 20 Gy (2000 rad) of external beam irradiation delivered to patients with choroidal melanomas prior to enucleation was investigated in 11 patients whose tumors were grown in cell culture. Phase-contrast microscopy was used to compare growth patterns between irradiated and nonirradiated tumors. Cell types were determined by histologic stains, and electron microscopy identified intracytoplasmic melanin. Irradiated melanomas did not grow and did not attach to culture flasks, thus demonstrating that preenucleation irradiation alters the in vitro growth of melanoma cells.

Surgery for coronary artery disease in patients with diabetes mellitus.

The results of surgery for occlusive coronary artery disease were studied in 600 consecutive, unselected patients who underwent aortocoronary bypass grafting between Jan. 1, 1977 and Dec. 31, 1982. Forty (7%) of these patients had diabetes mellitus, requiring medication. Sixteen of the 40 patients were insulin-dependent, the remainder required oral hypoglycemic agents. The frequency of previous myocardial infarction, hypertension and peripheral vascular disease in the groups of nondiabetic and diabetic patients was 38% and 62.5%, 12% and 22.5%, and 10.5% and 25% respectively. There was no significant difference in the rate of unstable angina, triple-vessel disease, emergency surgery, left ventricular dysfunction, myocardial infarction perioperatively and hospital morbidity or mortality in the two groups. On coronary angiography, 82% of coronary arteries in diabetic patients were graded as being small or moderate in size (less than 2 mm in diameter); at operation, 62% of these arteries were found to be 2 mm or more in diameter. At a mean follow-up of 3.9 years and 3.7 years in the nondiabetic and diabetic patients respectively (range from 1 to 6 years), no significant difference was noted with regard to relief of symptoms or survival in the two groups. It is concluded that diabetic patients with coronary artery disease can be offered bypass surgery with good short-term and medium-term results.

Avulsion of a normal aortic valve cusp due to blunt chest injury.

The successful operative treatment of aortic valve disruption caused by forceful blunt chest trauma in a 30-year-old previously healthy man is reported. The patients' left coronary cusp was completely avulsed at its annular insertion. Aortic valve replacement with a 23-mm Carpentier-Edwards porcine xenograft was performed. The literature on this rare condition is reviewed.

Cyclosporine in cardiac transplantation.

Since 1981 the authors have performed 14 orthotopic heart transplantations and one heart-lung transplantation, using cyclosporine and prednisone as immunosuppressants. Eight of the recipients had terminal congestive cardiomyopathy and six had ischemic cardiac dysfunction. The combined heart-lung transplantation was performed on a patient with a congenital ventricular septal defect with Eisenmenger's syndrome. Twelve of the patients were alive and well at follow-up 9 to 34 months (mean 17.4 months) after transplantation. One patient died of acute rejection and one of acute pancreatitis and secondary peritonitis. The third death, due to acute right ventricular failure, occurred immediately after transplantation. Rejection was diagnosed histologically on seven other occasions in four patients and was treated successfully. Infection was not a major problem. Cyclosporine -induced reversible nephrotoxicity was evident in 12 patients, 2 of whom required dialysis. Other side effects of cyclosporine seen in these patients included hypertension, gastrointestinal upset, headaches and hirsutism. This experience suggests that cyclosporine is a potent immunosuppressive agent that has greatly reduced the hazards of rejection and infection. However, the frequency of nephrotoxicity is high; careful monitoring of cyclosporine blood levels and renal function is essential.

Type I left ventricular rupture after mitral valve replacement.

Rupture of the left ventricle in the atrioventricular (AV) groove is a rare and usually fatal complication of mitral valve replacement (MVR). The successful repair of a delayed type I left ventricular rupture is described. The technique of repair is described, the literature reviewed, and three further cases from the authors' experience are reported.