Homograft failure in mycotic aortic aneurysm caused by Streptococcus pneumoniae

Treatment of a rare Streptococcus pneumoniae mycotic aneurysm by homograft replacement failed in a 59-year-old patient because of persistent lobar pneumonia. Despite reoperation with replacement of the infected homograft by a fresh one, he finally died of septicemia. This case illustrates that homograft tissue may be infected per continuum and that extensive debridement of periaortic tissue-including major lung resection-and the use of muscle flaps may be necessary in certain circumstances.

Transit-time flow measurement for detection of early graft failure during myocardial revascularization

BACKGROUND

A low-flow situation in arterial and venous grafts has been associated with high rates of perioperative infarction and mortality. This study was designed to look at intraoperative graft flow and resistance in patients with coronary artery disease.

METHODS

Coronary artery bypass graft flow was measured in 46 patients. Transit-time flow was used for coronary flow measurements at rest as well as after maximal vasodilation with adenosine infusion.

RESULTS

Forty-three of the 46 patients showed normal internal mammary artery graft flow (>20 mL/min); 3 patients had no or minimal graft flow. Redoing the graft anastomosis in these 3 patients resulted in normalization of graft flow. The mean flow increased significantly after correction from 0.5 +/- 0.7 mL/min to 15.7 +/- 9.6 mL/min (p < 0.02). Conversely, vascular resistance decreased significantly from 138 +/- 10 to 4.8 +/- 1.8 Ohmv (p < 0.0001), as did the pulsatility index (from 146.9 +/- 95.7 to 3.4 +/- 1.8; p < 0.001). After correction, coronary flow reserve was 2.5 +/- 1.1.

CONCLUSIONS

Measurements of intraoperative flow and resistance as well as derived variables allow assessment of early graft function and thus help prevent graft failure and reduce perioperative infarction. Transit-time volume flow might be a simple tool for quality control in coronary bypass procedures.

Aprotinin in pediatric cardiac operations: a benefit in complex malformations and with high-dose regimen only

BACKGROUND

The benefits and the current indications of aprotinin in congenital operations are not well defined. At present there are only a few studies available that have investigated a small number of patients in several heterogeneous groups of malformations.

METHODS

We investigated efficacy and safety of aprotinin in three groups of children < 15 kg, presenting with isolated ventricular septum defect (n = 60), tetralogy of Fallot (n = 52), and transposition of the great arteries (n = 56). Low-dose aprotinin regimen A1 (500,000 KIU in pump prime only) and high-dose aprotinin A2 (50,000 KIU/kg during induction of anesthesia, 50,000 KIU/kg in pump prime, and 20,000 KIU/h continuous infusion) were compared to a control group A0 (without aprotinin) regarding perioperative blood loss, transfusion requirements, and effects on the coagulation system.

RESULTS

The most common coagulation tests of aprotinin-treated patients and the platelet numbers were comparable with those of control patients preoperatively and 15 minutes after protamine administration. A significant dose-dependent reduction in fibrin-fibrinogen split products was observed at the end of cardiopulmonary bypass in the majority of aprotinin-treated patients with transposition. In patients with ventricular septum defect and Fallot, no significant difference in blood loss and transfusion requirements could be observed between patients with or without aprotinin and no difference was observed between low- and high-dose regimen. In transposition of the great arteries, high-dose aprotinin led to significant reduction of blood loss (p = 0.02) and postoperative blood transfusion (p = 0.003). Severe side effects as a result of administration of aprotinin were not observed.

CONCLUSIONS

High-dose aprotinin reduces blood loss and transfusion requirement only in complex congenital cardiac operations; therefore aprotinin cannot be recommended as a blood conservation agent in routine pediatric operations.

Intraoperative assessment of intestinal viability by laser Doppler flowmetry for surgery of ruptured abdominal aortic aneurysms

Ischemic colitis is a well known complication following surgery of ruptured abdominal aortic aneurysms, occurring in up to 60% of these patients. It is caused by failure to restore adequate blood flow to the watershed areas of the sigmoid colon. The purpose of this prospective study was to investigate erythrocyte flux to defined areas of the colon immediately after repair of ruptured abdominal aortic aneurysms using laser Doppler flowmetry (LDF) and to determine the critical level of erythrocyte flux below which revascularization of the colon is indicated. A group of 22 patients with a ruptured infrarenal aortic aneurysm in whom the inferior mesenteric artery was ligated at surgery were studied prospectively. Multiple LDF measurements of bowel blood flow (four per bowel segment) were performed on 103 intestinal segments intraoperatively using a Periflux 4001 Master with a PF 415:1 probe. In addition, histologic findings of ischemically injured intestine biopsied at routine postoperative endoscopy or postmortem examination were compared with the LDF records. There was a 41% incidence (9/22 patients) of postoperative colonic ischemia with a significant decrease in colonic erythrocyte flux below 50 perfusion units (PU) intraoperatively in all nine patients (100%). Four patients had transmural colon necrosis, and two patients died, for an overall mortality of 27%. Five patients were identified as having mild or moderate intestinal ischemia and were treated conservatively. Another 14 patients had no clinical or endoscopic signs of ischemic colitis. Erythrocyte flux in those colonic segments were > 50 PU. An intraoperative LDF recording of < 50 PU achieved a sensitivity of 100% (32/32 colon segments) and a positive prediction value of 100% in patients who developed ischemic colitis after surgery for ruptured abdominal aortic aneurysms. The results of this study demonstrate that LDF is a sensitive guide to and feasible method for evaluating critical colonic blood flow during repair of ruptured abdominal aortic aneurysm. The critical level of microvascular perfusion of the colon wall was found to be around 50 PU, below which revascularization of the colon should be considered to reduce the risk of subsequent ischemic colitis.

Infected endocardial pacemaker electrodes: successful open intracardiac removal

The long-term results after open intracardiac removal of infected pacing electrodes are presented.

METHODS

Between 1985 and 1990 open intracardiac removal of 19 infected pacing electrodes was performed in seven patients (six male and one female), with a mean age of 56 years. The indications were: persisting bacteremia in three; generator pocket infection in four; endocarditis in one; and ventricular tachycardia caused by retracted electrodes in one. All electrodes were fixed in the right heart and extraction by closed methods failed. Percutaneous catheter techniques were not applied in these seven patients. In five patients two ventricular electrodes had to be removed, and in two patients a single one. A total of seven atrial electrodes were removed in six patients (one electrode each in five patients; two electrodes in one patient). All atrial and two ventricular electrodes could be removed through a pursestring suture without use of a pump oxygenator. For the removal of ten ventricular electrodes in six patients (two electrodes each in four patients; 1 electrode each in two patients) a right-sided atriotomy was necessary with cardiopulmonary bypass (CPB). Simultaneously, five new pacing systems were implanted.

RESULTS

There were no early or late mortalities. In January 1991, all seven patients are alive and in a mean New York Heart Association Class 1,3 of heart failure after a mean interval of 33 months. In all cases the infection could controlled with a simultaneous antimicrobial chemotherapy and the postoperative period was free of major complications.

CONCLUSION

Open intracardiac removal of retained pacing electrodes with or without use of CPB is a safe procedure without major complications. It is mandatory for all infected pacing electrodes that cannot be extracted by closed methods.

Fatal fungal pericarditis after cardiac surgery and immunosuppression

The cases of two patients with fulminant pericarditis after cardiac surgery are reported. Both fungal infections developed after rethoracotomy for open-chest cardiac resuscitation and high-dose glucocorticoid treatment. Although the time course of both infections from the inoculation of fungi during rethoracotomy and immunosuppression with glucocorticoids to the lethal outcome was strikingly similar, histopathologic studies disclosed the disparate character of the two fungal pathogens responsible: the yeast Candida albicans and the angiotropic mold Aspergillus fumigatus.