The dynamic air bubble trap reduces cerebral microembolism during cardiopulmonary bypass.

OBJECTIVE: Neuropsychologic disorders are common after coronary artery bypass operations. Air microbubbles are identified as a contributing factor. A dynamic bubble trap might reduce the number of gaseous microemboli. METHODS: A total of 50 patients undergoing coronary artery bypass operation were recruited for this study. In 26 patients a dynamic bubble trap was placed between the arterial filter and the aortic cannula (group 1), and in 24 patients a placebo dynamic bubble trap was used (group 2). The number of high-intensity transient signals within the proximal middle cerebral artery was continuously measured on both sides during bypass, which was separated into 4 periods: phase 1, start of bypass until aortic clamping; phase 2, aortic clamping until rewarming; phase 3, rewarming until clamp removal; and phase 4, clamp removal until end of bypass. S100 beta values were measured before, immediately after, and 6 and 48 hours after the operation and before hospital discharge. RESULTS: The bubble elimination rate during bypass was 77% in group 1 and 28% in group 2 (P <.0001). The number of high-intensity signals was lower in group 1 during phase 1 (5.8 +/- 7.3 vs 16 +/- 15.4, P <.05 vs group 2) and phase 2 (6.9 +/- 7.3 vs 24.2 +/- 27.3, P <.05 vs group 2) but not during phases 3 and 4. Serum S100 beta values were equally increased in both groups immediately after the operation. Group 2 patients had higher S100 beta values 6 hours after the operation and significantly higher S100 beta values 48 hours after the operation (0.06 +/- 0.14 vs 0.18 +/- 0.24, P =.0133 vs group 2). Age and S100 beta values were correlated in group 2 but not in group 1. CONCLUSION: Gaseous microemboli can be removed with a dynamic bubble trap. Subclinical cerebral injury detectable by increases of S100 beta disappears earlier after surgical intervention.

Thrombotic formations within the aortic arch as source of embolization in patients with coagulopathia.

Thrombotic formations on atherosclerotic lesions of the thoracic aorta are potential sources of cerebral and systemic embolization. Especially younger patients without calcifications of atherosclerotic plaques or coagulation disorders have a higher risk for embolization. Magnetic resonance imaging and transesophageal echocardiography are the diagnostic methods of choice. As an alternative to anticoagulation surgical therapy is indicated to prevent severe brain damage or multiorgan failure in patients with mobile thrombotic formations. Herein we describe two patients in whom successful surgical treatment was performed in deep hypothermic circulatory arrest by excision of the aortic arch atheroma.

Long-term results after right ventricular outflow tract reconstruction with porcine bioprosthetic conduits.

From 1975 to 1990, a total of 110 patients were operated for complex cardiac malformations with impaired pulmonary artery perfusion using porcine valved right heart to pulmonary artery conduits. Twelve- to 30-mm porcine valved conduits (Hancock or Carpentier-Edwards) were implanted at the age of 4 weeks to 28 years (mean 4.3 years). The patients' body weights were 2.9-68 kg (mean 15.3 kg). Early mortality was 5.5% (six patients), late mortality was 12.7% (14 patients), and 90 patients could be included in this long-term follow-up (426 patient-years). So far, 41 of the conduits had to be exchanged 4 months to 15 years (mean 6.5 years) after the first implantation. Forty-nine of the conduits are still in place. At reoperation, 38 patients received an allograft; three patients, reoperated before 1982, had a second xenograft. The main reason for porcine conduit malfunction was degeneration and/or calcification of the valves. In 11 patients, however, with 12- and 14-mm conduits implanted at a mean age of 3.1 years, a reoperation was necessary after a mean time of 6.8 years because these children had "outgrown" the conduit and needed a bigger one. We conclude that even though allografts seem to be the conduit of choice for right ventricular outflow tract reconstruction, our clinical experience shows that porcine valved conduits can be used just as well since most of them function sufficiently well for as long as 5 to 10 years, and early valve failure is relatively rare.