The critical role of aprotinin in controlling haemostasis in conjunction with non-pharmacological blood-saving strategies during routine coronary artery bypass surgery

OBJECTIVE

Aprotinin, a non-specific serine protease inhibitor, has been confirmed to be safe and effective in reducing intra- and postoperative blood drainage, transfusion requirements, and perioperative morbidity and mortality during coronary artery bypass surgery. It is the only one of the currently available haemo-static agents that is approved by the U.S. Food and Drug Administration (FDA) for use in cardiac surgery. However, one major weakness of currently available trials is the lack of information regarding the concomitant usage of aprotinin with blood-saving strategies that have been used more frequently in recent years.

METHODS

Patients undergoing elective first-time coronary artery bypass grafting (n = 172) who were given systemic high-dose aprotinin (n = 85), combined systemic high-dose aprotinin and topical aprotinin (n = 27), or no aprotinin (n = 60) were reviewed retrospectively. The use of all blood-saving procedures was systematically taken in account.

RESULTS

Postoperative blood drainage was significantly less in patients treated with aprotinin than controls (P < 0.0001). Concomitant use of topical aprotinin was accompanied by a postoperative blood loss reduction of 35% compared to systemic aprotinin use alone (P < 0.003). The intra- and postoperative donor blood requirements were dramatically reduced in both aprotinin-treated groups compared to controls, although patients received different blood saving strategies as appropriate (P < 0.0001). A trend of up to 20% lower postoperative blood drainage was noted in patients in whom intraoperative haemodilution and autologuos blood transfusions were used (P > 0.05).

CONCLUSIONS

The present analysis demonstrates that the local and systemic administration of aprotinin is safe and effective in reducing intra- and postoperative blood drainage and transfusion requirements. In elective CABG procedures, aprotinin should still be used even if blood-saving strategies are employed.

Results of aortic valve replacement with pulmonary and aortic homografts

BACKGROUND AND AIM OF THE STUDY

Aortic valve replacement with cryopreserved human pulmonary or aortic valves (homografts) is an attractive alternative to the implantation of mechanical valves or bioprostheses, as anticoagulation can be avoided and a near-normal anatomy restored. However, few reports exist on the long-term follow up of patients with this type of valve.

METHODS

Between 1990 and 1997, a total of 64 homografts were implanted in 62 adults (mean age 42 +/- 12 years) with non-endocarditic valve lesions (insufficiency, n = 16; stenosis, n = 20; combined lesions, n = 12; redo, n = 16). In total, 23 pulmonary grafts (PG) and 41 aortic grafts (AG) were used. Valves were obtained from the European Homograft Bank in Brussels. Two patients with aortic homografts were lost to follow up; the others were examined clinically and echocardiographically at yearly intervals (mean 3.6 +/- 2.0 years). Children aged less than 16 years (n = 21), and patients receiving a homograft due to endocarditis (n = 28) or during a Ross procedure (n = 16) were excluded from the study.

RESULTS

Three patients (5%) died due to early postoperative complications (two with AG, one with PG). Three PG had to be explanted due to primary malfunction, and five (total 35%) during further follow up due to severe aortic insufficiency (at a mean of 3.3 +/- 1.8 years). In contrast, all AG were functioning at the end of the observation period (log rank test, p = 0.0001, chi-square test 13.9). The mean echocardiographic degree of regurgitation for PG was significantly higher than for AG (2.2 +/- 1 vs. 0.75 +/- 0.7, p <0.0001). The peak transvalvular gradient did not differ between groups (PG 12.3 +/- 9 mmHg vs. AG 16.7 +/- 10 mmHg, p = NS). In respect of perioperative parameters, patients with PG showed a significantly higher body temperature during the first seven postoperative days (37.3 +/- 0.6 degrees C vs. 36.8 +/- 0.3 degrees C, p = 0.003). All three patients with acute graft malfunction in long-term follow up had a perioperative febrile response without overt bacterial infection.

CONCLUSION

In contrast to grafts of aortic origin, pulmonary homograft valves should not be used for aortic valve replacement because of their high rate of malfunction, both acutely and chronically. Higher postoperative body temperatures should lead to further investigations of possible enhanced immunoreactions against pulmonary homografts.

Banking of cryopreserved heart valves in Europe: assessment of a 10-year operation in the European Homograft Bank (EHB)

BACKGROUND AND AIM OF THE STUDY

The preparation, banking and distribution of cryopreserved heart valves has been carried out at the European Homograft Bank (EHB) in Brussels without interruption since January 1989. We present an assessment of the Bank's activities during this 10-year period.

METHODS

Heart valve donors aged <62 years form three categories: multiorgan donors with non-transplantable hearts; recipients of cardiac transplantation; and non-beating heart cadavers with a warm ischemia time of less than 6 h. Past history and biology are checked for transmissible diseases. Dissection, incubation in antibiotics and cryopreservation in 10% dimethylsulfoxide with storage in liquid nitrogen vapors (about -150 degrees C), and quality control are according to the standards of the Belgian Ministry of Health. Cryopreserved valves are shipped to the implantation centers in a dry shipper at about -150 degrees C.

RESULTS

Between January 30th 1989 and December 31st 1998, 1,817 non-transplantable hearts and 12 excised semilunar valves were obtained. In total, 2,077 valves (1,032 pulmonary, 931 aortic and 13 mitral) were decontaminated, cryopreserved and stored in liquid nitrogen vapor (six more valves were refrigerated). In total, 1,515 valves were discarded at different stages of the protocol, the main causes of rejection being significant macroscopic lesions (68.2% aortic and 26.67% pulmonary). Inadequate excision at procurement (10.37% pulmonary), persistent contamination after antibiotics (5.6%) and positive serology for hepatitis B and C and Q fever (5.4%) were other frequent causes for rejection. Among the 2,117 accepted valves, 1,398 were graded first and 719 second choice, mainly on the basis of morphology. In total, 2,090 cryopreserved valves and one refrigerated valve were implanted in 39 institutions between May 1989 and December 1998. Of requests, 10.02% could not be satisfied. In total, 967 pulmonary valves were implanted in the right ventricular outflow tract (RVOT); 424 during a Ross procedure, and 76 in the left ventricular outflow tract (LVOT). Of the aortic valves, 732 were implanted in the LVOT and 266 in the RVOT. Mitral homografts were used for tricuspid valve replacement in two cases, and in the mitral position in seven. Complications at distribution and thawing included 10 bag ruptures and 16 transversal conduit wall fractures. Of the valves shipped, 317 (13.16%) were not used and were returned safely in the dry shipper. Comparison of distribution rates in the first 5.5 and last 4.5 years of EHB activity shows: (i) a significant increase in pulmonary valve implantations in the RVOT (from 71.95% to 81.95%); and (ii) a marked increase (265%) in pulmonary homograft implantations as part of a Ross operation, and a significant decrease (28%) in aortic homograft implantation in the LVOT.

CONCLUSION

While macroscopic lesions of procured aortic valves remain the most frequent and unavoidable cause of homograft rejection during quality control, the high percentage of inadequate surgical heart valve excision should be corrected. The rates of bacterial contamination and positive serology seem acceptable. Storage and shipping of cryopreserved homografts in liquid nitrogen vapor permits them to be spared very efficiently. The increasing use of pulmonary valves for RVOT reconstruction either in congenital heart disease or as part of the Ross procedure compensates for the limited availability of good quality aortic valves.

Are pulmonary homografts which were subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? A long-term multicentric echography study

OBJECTIVE

To compare long-term results of the European Homograft Bank (LHB) cryopreserved pulmonary homograft in left ventricular outflow tract (LVOT) subjected to pulmonary hypertension with those subjected to normal pulmonary pressure. The mid-term study of this material published in 1997 showed different results.

METHODS

Statistical analysis is calculated by the Kaplan-Meier survival curves, while differences in prevalence by the Log-Rank test.

RESULTS

Follow-up (FU) was available in 69 cases (76.7%): 46 in group 1 and 23 in group 2. Five patients have been excluded from the study because of early homograft explantation (technical problems or early valve incompetence). Fourteen out of 43 cases of group 1 (32. 6%) and seven out of 21 cases of group 2 (33.3%) have been explanted after 2.5-88 months and 7-88 months, respectively. Significant echography changes have been found in 19 of 43 (44.18%) of group 1 and 11 of 21 cases (52.38%) of group 2 during the follow-up. Histology showed essentially wear and tear induced lesions. Mean FU was 36.9 (range, 6-88) and 41.3 months (range, 4-88) for group 1 and 2, respectively. No significant difference in the long-term outcome have been found between the two groups (P=0.38).

CONCLUSION

Contrary to our previous echocardiography study of mid-term implants the long-term follow up of the PHGs implanted in the LVOT did not show better function of the pulmonary homografts subjected to pulmonary hypertension than those with normal pulmonary pressure. The high failure rate of the PHGs should discourage their use for LVOT reconstruction. Further echocardiography studies of remaining PHGs implanted in the LVOT, and gross and microscopic explant studies are required to judge on the definitive outcome of these grafts.

Are pulmonary homografts subjected to pulmonary hypertension more appropriate for aortic valve replacement than normal pulmonary homografts? Results of echocardiography in a multicentric study

OBJECTIVE

To compare the function in aortic position of cryopreserved pulmonary homografts subjected to pulmonary hypertension with that of normal cryopreserved pulmonary homografts.

METHODS

Pulmonary valves (52) were implanted in aortic position in different cardiothoracic centres. The valves were classified as follows: Group I-pulmonary hypertension (procured from recipients of heart/heart-lung transplantation, 31 valves), Group II-normal pulmonary pressure (procured from cadavers and multiorgan donors, 21 valves). Regular echocardiographic follow-up was obtained by the implanting centers. Significant echo changes were defined as insufficiency > 2+ and/or stenosis producing a delta P > 30 mm Hg.

RESULTS

Pulmonary homografts showed the following significant echo changes: in the Pulmonary Hypertension Group, 7, 27 and 33% at 12, 24 and 36 months, respectively; in the normal PA Group 10, 37.5 and 80% at 12, 24 and 36 months, respectively. In both groups the most common echocardiographic alteration was homograft insufficiency rather than stenosis. Thus, pulmonary homografts subjected to long-term pulmonary hypertension have significantly less echo changes than normal pulmonary homografts, especially after 12 months (chi 2: P < 0.036).

CONCLUSIONS

These findings suggest that pulmonary valves subjected to pulmonary hypertension might be more appropriate than normal pulmonary homograft for aortic valve replacement, constituting a possible alternative in case of lack of aortic valve homografts. However, the failure of two out of five valves in the longer term must dictate caution while waiting further long-term results.

Epidemiology of invasive mycosis in ICU patients: a prospective multicenter study in 435 non-neutropenic patients. Paul-Ehrlich Society for Chemotherapy, Divisions of Mycology and Pneumonia Research

OBJECTIVE

To determine the epidemiological and clinical significance of invasive fungal infections in non-neutropenic patients in intensive care who stay longer than 10 days on the intensive care unit (ICU).

DESIGN

Prospective epidemiological multicenter study over a period of 11 months, based on strict clinical, bacteriological, serological and histological criteria.

SETTING

Six surgical and two medical ICUs units in five university and two municipal hospitals.

PATIENTS

435 non-neutropenic patients from medical and surgical ICUs with an ICU stay of more than 10 days.

MEASUREMENTS AND MAIN RESULTS

A new occurrence of invasive mycosis (3 sepsis/4 peritonitis/1 disseminated candidiasis), corresponding to the protocol conditions with onset after day 10 in the ICU, was detectable in 2.0% (95% confidence interval 0.85 to 3.8%) of the 409 patients who could be assessed. Candida species were identified as an infection-relevant pathogen in all cases. The most important risk factor for the development of an invasive mycosis was the onset of peritonitis by the day 11 in the ICU (odds ratio 11.3; p = 0.003). A fungal colonization was detected in 64% of patients (Candida species 56%, Aspergillus 4%, and other fungi). Six of 8 patients with an invasive mycosis died on the ICU; ICU mortality in patients with fungal colonization was 31% and in noncolonized patients 26%. Serological tests were not helpful clinically. The sensitivity was 88% for the Candida HAT (haemagglutination test) (threshold titer > 1:160), 100% for the Candida IFT (immunofluorescence test) (threshold titer > 1:80), and 50% for the Candida Antigen Test (Candtec Ramco, threshold titer > or = 1:8), and the specificity was 26, 6, and 73%, respectively. The specificity for the Aspergillus HAT (threshold titer > 1:10) was 29%.

CONCLUSIONS

Invasive mycoses are rare in non-neutropenic ICU patients, even after a longer stay in the intensive care unit; fungal colonization, on the other hand, is frequently detectable. The mortality of invasive mycosis--even with systemic antimycotic therapy--was high; the mortality in patients with fungal colonization was not significantly increased compared to that in noncolonized patients. The serological test procedures, Candida HAT, Candida IFT, and the Candida Ramco Antigen Test, had a low specificity and were not helpful in diagnosing relevant invasive mycosis.

[Transmyocardial laser revascularization--a treatment option for coronary heart disease?]

Transmyocardial laser revascularization (TMR) is a new therapeutic principle for patients with coronary artery disease and no possibility of conventional revascularization with CABG or PTCA. The clinical value of the method is not known. Therefore we investigated all 46 patients treated with sole TMR in our center using clinical investigation, LV and coronary angiography, right heart catheterization, MIBI perfusion imaging and myocardial FDG-PET pre- and 6 months post TMR. 117 patients judged not suitable for conventional revascularization procedures were submitted for TMR. The indication for the procedure was reevaluated in every case. 52 patients (mean EF 41 +/- 16%) could be further treated by intensified anti-anginal medication, seven patients received bypass grafts, four patients had PTCA, three patients were listed for heart transplantation, and five patients had a combined CABG plus TMR. Only 46 (38% of the submitted patients, mean EF 55 +/- 15%) were accepted for sole TMR. CCS class of these patients was 3.3 +/- 0.4, mean age was 63.6 +/- 7.3 years, 70% were males. The postoperative mortality within 30 days was 5/46 (10.8%); 9/46 patients (19.5%) suffered from perioperative myocardial infarction. Other complications were ventricular fibrillation in two cases on the second postoperative day and a rupture of the spleen on the 14th postoperative day. 8/46 patients (17%) had wound infections. Survivors showed an improvement in their CCS class (1.9, 2.1, 1.9 after 3, 6 and 12 months, respectively, mean observation time 0.61 +/- 0.4 years). These patients were able to perform bicycle stress tests significantly longer (98 s +/- 9 pre versus 120 +/- 13 s post TMR, p = 0.01). Angiographic EF fell from 57.8% +/- 15% to 52.6% +/- 19% (p = 0.02) and the number of hypokinetic chords rose from 23.6 +/- 20.9% to 30.6 +/- 24.1% per patient (p = 0.008), predominantly in the inferior wall. Nuclear studies showed reduced myocardial perfusion and vitality after TMR. Four patients in the TMR group had reintervention (PTCA) because of progression of coronary sclerosis of native vessels. One patient had mitral valve replacement due to severe regurgitation. Kaplan-Meier analysis showed no significant difference in survival between the TMR and the medical group when stratified according to initial ejection fraction. Sudden death and congestive heart failure are the most important causes of mortality. Our data show that TMR improves symptoms and exercise performance of otherwise not treatable patients with diffuse coronary artery disease. Due to a lack of an improvement of cardiac perfusion, function or prognosis TMR should be used only in highly selected cases when conventional methods fail to improve patients symptoms.

Abdominal aortic aneurysm repair after renal transplantation with extracorporeal bypass

The successful resection of an abdominal aortic aneurysm is presented in a patient who had undergone kidney transplantation 4 years previously. Because the transplanted kidney is more sensitive to ischemia than a normal one, a femoro-femoral bypass with a pump oxygenator was used for perfusion of the transplanted kidney during crossclamping. During the clamping time of 40 minutes kidney perfusion was maintained with a perfusion pressure of 60 to 80 mmHg and the flow was 600 to 1000 ml/min. A collagen-seeded Dacron graft (diameter: 18 mm, length: 12 mm) was interposed. The postoperative course was uncomplicated. We believe that performing the femoro-femoral bypass with a pump oxygenator is an effective and simple method for kidney protection in such operations.

Delayed coronary occlusion following primary successful angioplasty: management and outcome

The treatment of delayed coronary occlusion after primary successful percutaneous transluminal coronary angioplasty (PTCA) is more difficult because surgical standby is often not available. The purpose of this study was to assess the therapeutic approaches and outcome of patients with delayed coronary occlusion from 30 to 180 minutes after successful PTCA. A delayed occlusion occurred in 18 (0.9%) (61 +/- 11 years; male n = 14, female n = 4) out of 2065 consecutive patients after PTCA. In 11 patients the dilated stenoses were located in the left descending artery, while seven patients had the stenosis in the right coronary artery. Twelve patients had unstable or postinfarction angina. The time interval between completion of PTCA and the onset of chest pain was 64 +/- 39 minutes. Immediate i.v. nitroglycerin resulted in no relief of the symptoms in any patient. One patient was operated upon at once, and one was given i.v. thrombolysis resulting in pain relief and reversal of ECG changes. The remaining 16 patients returned initially to the catheterization laboratory, where the occluded vessels were opened by mechanical recanalization. Three of them remained in stable condition. Due to impending reocclusion surgery was necessary in four patients and thrombolysis was performed in nine. After thrombolysis the vessel remained open in four patients. The other five needed bypass surgery on the day of PTCA. Myocardial infarction developed in nine patients (maximal CK 673 +/- 488 units/l). In conclusion, delayed occlusion after successful PTCA is a rare complication occurring primarily in patients with unstable angina. Mechanical recanalization opened the occluded vessel in most patients, and myocardial infarction was prevented in 50%.

[Results of emergency bypass operation following percutaneous transluminal coronary angioplasty]

Between 1980 and 1988, percutaneous transluminal coronary angioplasty (PTCA) was performed in 1,514 patients. Fifty-five patients (3.6%) underwent emergency coronary bypass surgery because of an acute occlusion of the vessel or a dissection with sustained angina and signs of ischemia on the electrocardiogram. Twenty-five of these 55 patients had a myocardial infarction and 5 patients died, 3 perioperatively, 2 after hospital discharge. The degree of stenosis of the dilated vessel significantly influenced the incidence of infarction, while left ventricular ejection fraction prior to PTCA significantly influenced mortality. Patients who underwent surgery with an occluded vessel experienced myocardial infarction significantly more often (87%) than patients with a patent vessel (24%). The incidence of infarction was 27% when reperfusion of the vessel occluded during PTCA was achieved with a reperfusion catheter, repeated PTCA or intracoronary lysis. The patients' age, presence of unstable angina, left ventricular ejection fraction prior to PTCA, the dilated vessel, the extent of coronary artery disease, collateralization of the dilated vessel, and the time between the onset of the event necessitating bypass surgery and the beginning of extracorporeal circulation were found to have no influence on the incidence of infarction. Patients who died had a significantly lower ejection fraction before PTCA than survivors and all patients who died had experienced a large perioperative myocardial infarction.

New nomenclature and computerized programme of graphics for the description and recording of aortocoronary bypasses

In the process of drawing up a computerized operation reporting system, a nomenclature for the precise description of recently fitted or existing aortocoronary bypasses has been developed. This is based on a sequence of letters showing in one line which type of bypass has been fitted, the graft material used, the central anastomosis (source) as well as the peripheral anastomoses on the coronary arteries (objective). For this purpose, abbreviations of the customary terms in use in cardiac surgery have been used. A computer graphics programme has been created in parallel, enabling all bypasses (existing and/or new) to be sketched into the diagram of a heart with the aid of a mouse. The bypass nomenclature is automatically generated from the diagram, which can also be printed out as a sketch of the operation. The complete diagram of the heart plus data input forms enable the operation report to be compiled automatically. The nomenclature and the graphics programme are easily learnt, simplify work, can readily be incorporated into a computerized hospital organization and enhance documentation quality.

Multicentric quality assurance in cardiac surgery. QUADRA study of the German Society for Thoracic and Cardiovascular Surgery (QUADRA: quality data retrospective analysis)

A method for initiating quality assurance in cardiac surgery was developed multicentrically by a commission of the German Society for Thoracic and Cardiovascular Surgery (QUADRA Study). To appraise the quality of cardiosurgical action, variables were compiled from the preoperative, intraoperative, and postoperative treatment course. The data collection was carried out at the same time as treatment. On the basis of unicentric data profiles, multicentric hospital profiles, and problem profiles, a quality comparison could be carried out and the variability of cardiosurgical action which may occasion interventions could be identified. A reduction of perioperative blood consumption during the study period could be observed in four out of five hospitals as the first result. The data collection also revealed epidemiological features. On average, women were older than men at the time of the heart-valve and coronary operations. To ensure data validity and the organization of quality assurance, a documentation assistant and a specially trained physician are necessary at every cardiovascular surgery center. The multicentric external comparison is indispensable and must be carried out by means of a central data collection, for which intrumental and staff capacities are also to be provided. With modern methods of data processing, an additional and new approach to the improvement of quality in cardiac surgery can thus be made.

[Disorders of fascicular conduction following coronary surgery: etiology and clinical relevance]

Seventy-one consecutive patients undergoing coronary artery bypass grafting (CABG) were studied prospectively. New fascicular conduction defects (FCD) were evident in 51 patients (72%) 1 h after cardioplegic cardiac arrest, in 40 patients (56%) after 2 h, in 29 patients (41%) on the first postoperative day, and in 14 patients (20%) on the seventh postoperative day. Right bundle branch block was the most common type of FCD, followed by left anterior hemiblock. FCD were related to longer aortic cross-clamp time, higher age (p less than 0.025), frequency of wall motion abnormalities (p = 0.033), the number of diseased (p = 0.007) and bypassed vessels (p less than 0.0005), a greater intra- (p = 0.018) and postoperative (p = 0.017) demand for catecholamines, a more complicated postoperative course (p = 0.005), and a longer stay in the intensive care unit (p less than 0.01). Ischemic damage to the conduction system during cardioplegic cardiac arrest appears to be the most likely explanation for new FCD after CABG. Severe coronary heart disease contributes to their development. Hence, adequate myocardial preservation is of crucial importance. FCD are associated with increased perioperative morbidity, according to other studies, also with poorer long-term prognosis, especially in case of a left bundle branch block. In this subset a closer follow-up may be indicated.

Increase in myocardial Gi-proteins in heart failure

The contractile response and myocardial content of Gi-proteins were examined in cardiac preparations from explanted hearts of four different patients with end-stage heart failure. Three patients had idiopathic dilated cardiomyopathy and one patient had inflammatory heart disease. Preparations from patients with idiopathic dilated cardiomyopathy showed reduced contractile response to the cAMP-increasing agent isoprenaline and an increase in myocardial Gi-proteins, compared with preparations from non-failing hearts. Therefore it is conceivable that an increase in myocardial Gi-proteins is causally related to heart failure due to idiopathic dilated cardiomyopathy. In the preparation from the patient with inflammatory heart disease the contractile response to isoprenaline was not reduced and likewise content of Gi-proteins was not changed.

'Head and heart'--neurological and psychological reactions to open heart surgery

Neurological and psychological reactions to open-heart surgery are widely underestimated phenomena and occur in a much higher incidence than one might expect. When analyzed retrospectively, up to 3.8% of patients who underwent cardiac surgery at the Hamburg University Hospital exhibited these reactions, whereas 35%-50% presented with symptoms and signs of perioperative CNS dysfunctions in prospective studies at our department. About the same percentages are detected in prospective studies of the patients' perioperative psychopathology, stating that a great number of cardiac patients exceed the normal range of anxious, tense, and depressive moods in this setting. The consequences of these findings for the patients' quality of life and the impact for the perioperative management of patients undergoing open-heart surgery are discussed. The current prospective studies, preliminary results of which are presented here, are part of an international interdisciplinary study, initiated to bring more light into the complicated relations between ECC-assisted cardiac surgery, anaesthesiology, neurology and psychology.

[Intracoronary thrombus in patients with unstable angina pectoris]

Intracoronary thrombi were found in 20 of 52 patients (38%) who had coronary angiography because of treatment-resistant unstable angina. Unrelated to the angiographic finding, eight patients (15%) sustained a myocardial infarction, and two died during their hospital stay. Only one patient (5%) with and six patients (19%) without intracoronary thrombi were stabilized and discharged from hospital. The remaining patients either had an aortocoronary bypass (n = 31) or transluminal balloon angioplasty (n = 13). These findings underline the importance of intracoronary thrombus formation in the pathogenesis of treatment-resistant unstable angina.

[Arterial digital subtraction angiography for demonstrating aortocoronary venous bypasses]

We examined the patency of aortocoronary venous bypasses in 51 patients during the early postoperative phase by using non-selective contrast injection into the aorta with digital subtraction angiography. In all patients it was possible to evaluate the degree of patency by this method. The accuracy and value of this examination, as compared with other invasive and non-invasive methods, is discussed.

Intracoronary thallium 201 scintigraphy as an immediate predictor of salvaged myocardium following intracoronary lysis

Since February of 1980, 157 patients who had had symptoms of acute myocardial infarction for less than 3 hours underwent intracoronary lysis. Forty-six patients required early aorta-coronary revascularization. However, operation was believed to be indicated only when intracoronary lysis was successful and myocardium was salvaged. Since left ventricular angiography proved unreliable in assessing the viability of the myocardium in the acute stage, starting in March of 1981 we obtained intracoronary thallium 201 scintiscans in 23 patients before and after intracoronary lysis. Patients in whom there was a significant reduction (greater than 50%) in the initial 201Th defect (n = 12) were considered ideal candidates for operation (Group 3). Patients with poor or unimproved 201Th uptake after successful intracoronary lysis (n = 6) were treated medically (Group 2), as were patients in whom intracoronary lysis was unsuccessful (n = 5, Group 1). In order to validate this new approach, we compared the change in the regional wall motion of the "infarcted area," as shown in the early and follow-up left ventricular angiograms in all three groups. In the acute stage, the mean regional ejection fraction was 19.9% in Group 1, 19.1% in Group 2, and 20.1% in Group 3. Only in Group 3 was there a significant increase in regional ejection fraction to a mean of 51%. The mean ejection fraction obtained at follow-up in Groups 1 and 2 was 16.5% and 17.3%, respectively. From our findings, we conclude that 201Th scintigraphy is a valuable predictor of the salvageability of myocardium immediately following intracoronary lysis. To date, it has been the most valuable tool in assessing those patients suitable for early coronary revascularization.

Transesophageal two-dimensional echocardiography in the diagnosis of cor triatriatum in the adult

Two adult patients with left ventricular inflow obstruction are presented. Conventional two-dimensional echocardiography had failed to yield a definite diagnosis, whereas transesophageal two-dimensional echocardiography clearly documented a membraneous echo structure within the left atrium, diagnostic of cor triatriatum. On the basis of the transesophageal echocardiographic findings, left heart catheterization and angiocardiography were not performed and both patients successfully underwent cardiac surgery.

[Demonstration of neo-intima in PTFE-prostheses after venous replacement in dogs]

Because of the danger of thrombosis, venous replacement by prostheses is a yet clinically unsolved problem. We tested the PTFE-prosthesis at the positions of vena cava inferior and iliac veins in dogs. Already eight weeks after operation, the inner surface of the prosthesis was covered by a thin neo-intima, which by light microscopy, scanning and transmission electron microscopy was shown to contain a basal membrane and endothelial cells. This continuous layer may be responsible for the observed low rate of thrombosis. These findings suggest that the PTFE-prosthesis may offer advantages for venous replacement in patients.

[Wound infection and its treatment. In thoracic and cardiovascular surgery]

Wound infections following aseptic operations are considered to be hospital infections. Among 4,166 patients operated on between 1973 and 1980 for cardiovascular diseases, there have been wound infections in 58 cases (1.4%) and associated sternal or mediastinal infection in 11 cases (0.26%). One-third of the infections were caused by staphylococci. In superficial infections therapy consisted in healing by second intention. In deep infections surgical intervention with débridement and irrigation was the method of choice.

Bioadhesives in cardiac and vascular surgery

Bleeding through the pores of thoracic vascular grafts sealed with bioadhesive has been eliminated without inducing additional defects in the coagulation system. This has been true regardless of whether additional valve replacement or aorto-coronary bypass procedures were performed. The operative risk and the need for blood transfusions has been lowered significantly thus reducing the cost of these procedures. Bioadhesive has been also applied successfully in a variety of perioperative bleeding complications.

[Perioperative complete right bundle branch block after aorto-coronary bypass surgery (author's transl)]

In 322 patients undergoing isolated coronary artery bypass grafting, the possible factors responsible for the development of intraventricular conduction disturbances were investigated. In 18 patients (5.6%), complete right bundle branch was observed perioperatively, 2 of whom also demonstrated left anterior hemiblock. Left bundle branch block, either complete or incomplete, was not observed. Patients demonstrating perioperative complete right bundle branch block were further characterized by the finding that 14 of 18 (77.7%) had preoperative inferior wall infarction as opposed to only 34% in the remaining 304 patients. Fifteen of the 18 patients (83.3%) had prolonged aortic cross-clamp times in contrast to only 37.5% of the remaining patients. Three-vessel disease, present in 16 of the 18 (88.9%) patients, was less frequently present (56.2%) in those in whom complete right bundle branch block did not develop perioperatively. Application of the chi 2-test showed significant differences in all of the latter variables. The perioperative onset of complete right bundle branch block may be due to several factors. The results of this study indicate that the extent of scar tissue and arteriosclerotic changes as well as the ischemic time during surgery may play a decisive role. In ten of the patients, the perioperatively-incurred complete right bundle branch block was irreversible. Postoperative angiographic studies revealed no relationship between block development and graft occlusion.

[Use of mezlocillin in open heart surgery (author's transl)]

Concentrations of mezlocillin in serum and heart tissue were studied in 29 patients undergoing open heart surgery. The antibiotic agent was administered three times as a bolus injection of 2 grams each: after induction of anaesthesia, after initiation of extracorporeal bypass (ECC) and shortly after discontinuation of ECC. Serum levels were measured in 25 patients from samples drawn 30 minutes after the bolus injection and subsequently biologic assays were carried out by the agar diffusion method. The mean initial values during the three phases of surgery were 119.2, 170.6 and 236.0 micrograms/ml, respectively; at 60 minutes the values were 61.3, 100.8 and 101.9 micrograms/ml. Calculation of the exponential curve enabled a mathematical comparison of the half-life of the substance during the pre-ECC, ECC and post-ECC periods. The most rapid elimination was found to occur prior to initiation of ECC, the slowest during ECC, while in the post-ECC period the elimination was similar to, but somewhat slower than that of, the pre-ECC period. The concentration, measured in the tissue of eleven aortic valves, averaged 35.96 (range 8.4 to 63.4) micrograms/ml. The mean concentration found in papillary muscles of the left ventricle, resected at the time of mitral valve replacement in six patients, was 31.54% (range 17.7 to 58.33) micrograms/ml. Mean tissue concentration found in five resected mitral valves was 43.77 (range 27.33 to 71.5) micrograms/ml. The findings indicate that mezlocillin, administered as described, will reach serum and tissue concentrations at all periods of open heart surgery well above those of the minimum inhibitory concentration of most clinically relevant bacteria.