Optimum load in various vertical jumps support the maximum dynamic output hypothesis.

The aim was to generalize the maximum dynamic output (MDO) hypothesis [i. e., the muscle power output in vertical jumps (VJ) is maximized when loaded with one's own body mass] to variety of VJ. We hypothesized that the subjects' own body (a) would be the optimal load for maximizing the power output (i. e., the no-load condition) and also (b) reveal the maximum benefits of stretch-shortening cycle (SSC). 13 participants performed the maximum squat and various counter-movement jumps when loaded by approximately constant external force ranging from -40% to + 40% of their body weight (BW). Regarding the first hypothesis, the differences in both the peak and mean power recorded under different load magnitudes revealed maxima close to no-load condition (i. e., from -3% BW to + 8% BW; R2=0.65-0.96; all P<0.01). Regarding the second hypothesis, the differences in performance between VJ executed with and without SSC also revealed maxima close to no-load conditions (0-2% BW), while the same differences in the power output were observed under relatively low positive loads (14-25% BW; R² = 0.56-0.95; all P<0.01). The findings support the concept that maximal power output occurs close to one's own body mass during VJ with and without SSC, thereby providing additional support to MDO hypothesis.

Transcranial Doppler sound detection of cerebral microembolism during transapical aortic valve implantation.

OBJECTIVE: Transapical aortic valve implantation (TAVI) is a new method that might reduce the surgical risk of conventional surgical aortic valve replacement in very high-risk patients. Increased downstream microembolization is expected in transapical aortic valve implantation. However, whether it usually occurs, how often, and its clinical relevance are not known. We report the results of ultrasound microembolic signal detection in the middle cerebral artery during the procedure. METHODS: Fifty patients (mean age: 80 ± 5 years; mean EuroSCORE: 36 ± 13 %) underwent transapical aortic valve implantation. Intraoperative transcranial Doppler (TCD) sound examination of both middle cerebral arteries (MCA) was used to identify high-intensity transient signals (HITS) and microembolic signals (MES) during seven phases of the procedure. Pre- and postoperative computed tomography of the brain and clinical neurological examinations were performed preoperatively and daily during the first postoperative week. RESULTS: During the procedure, HITS [right MCA: 435 ± 922 (range 9-5765); left MCA: 471 ± 996 (range 24-6432)] and MES [right MCA: 78 ± 172 (range 1-955); left MCA: 62 ± 190 (range 2-1553)] were detected in all patients. Most of the MES were recorded during valvuloplasty [right MCA: 3 ± 5.6 (range 0-31); left MCA: 2 ± 4.9 (range 0-30)] and positioning of the prosthetic valve in the aortic position [right MCA: 6 ± 5 (range 0-22); left MCA: 2 ± 6.9 (range 0-38)]. Postoperatively, there were no clinical signs of new cerebral embolism. CONCLUSIONS: Cerebral microemboli were detected by intraoperative transcranial Doppler sound examinations in all patients during transapical aortic valve implantation. Most of the signals were detected during balloon valvuloplasty and delivery of the prosthetic valve.

[Improvements in implantable mechanical circulatory support systems : literature overview and update]. / Fortschritte bei implantierbaren mechanischen Kreislaufunterstüzungssystemen : Literaturübersicht und Update.

In recent years, ventricular assist devices (VAD) supporting the left (LVAD), the right (RVAD) or both ventricles (BVAD) have rapidly emerged as the standard of care for advanced heart failure patients. Both the numbers and ages of patients in which they are used are rising worldwide, especially when used as a permanent support (bridge to destination, BTD). Due to the continuing lack of donor organs, these devices now represent a viable alternative to bridge patients to transplantation (BTT), with a 1-year survival rate of 86%. BTD, especially in long-term support, might be a valid, and the sole, option for those patients in whom heart transplantation is contraindicated. Patient selection, pre- and intra-operative preparation, as well as the timing of VAD implantation are important factors critical to successful circulatory support. While BTT remains the goal in the majority of patients, the number of permanent VADs (i. e. BTD) is rising significantly. Although explantation of a VAD system as a bridge to recovery (BTR) can be considered in only a small number of patients, it represents a very special part of this therapy modality.

A real-world assessment of procalcitonin combined with antimicrobial stewardship in a community ICU.

PURPOSE: We evaluated the feasibility and impact of PCT-guided antibiotic duration combined with an established antibiotic stewardship program (ASP) in a community hospital intensive care unit (ICU). METHODS: We implemented daily PCT levels for ICU patients receiving antibiotics. Our protocol recommended stopping antibiotic therapy if PCT met an absolute or relative stopping threshold. We evaluated the adherence to stopping criteria within 48 h, antibiotic use [days of therapy (DOT) per 1000 patient-days (PD)], length of stay and ICU-mortality. We performed interrupted time series analysis to compare 24 months before and 12 months after implementation. RESULTS: A total of 297 antibiotic courses were monitored with PCT in 217 patients. Protocol adherence was 34% (absolute threshold: 39%, relative threshold: 12%). Antibiotic use pre-PCT was 935 DOTs/1000 PDs and post-PCT was 817 DOTs/1000 PDs (RRadj 0.73, 95% CI: 0.62 to 0.86). No statistically significant changes in clinical outcomes were noted. CONCLUSION: In the context of an established ASP in a community hospital ICU, PCT monitoring was feasible and associated with an adjusted overall decrease of 27% in antibiotic use with no adverse impact on clinical outcomes. Incorporating PCT testing to guide antibiotic duration can be successful if integrated into workflow and paired with ASP guidance.

Transient sinus node dysfunction after the Cox-maze III procedure in patients with organic heart disease and chronic fixed atrial fibrillation.

OBJECTIVES: This prospective study examined types, frequency and time dependency of the electrophysiologic manifestation of the sinus node dysfunction after the Cox-maze III procedure--the technique of choice for the management of medically refractory atrial fibrillation-in patients with organic heart disease, chronic fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus node. BACKGROUND: The original maze procedure was modified twice in order to reduce the high incidence of the sinus node inability to generate an appropriate sinus tachycardia in response to maximal exercise, and occasional left atrial dysfunction. Despite these modifications, postoperative disturbance of sinus node function can be frequently observed. METHODS: In 15 adult patients, standard electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart variability, exercise testing, Valsalva maneuver and rapid positional changes were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral valve surgery or closure of atrial septal defect. RESULTS: Electrocardiographic manifestations of sinus node dysfunction were identified in 12 patients at 3 months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery. The heart rate response to exercise during the first 6 months was reduced in the maze group and became fully normal at 12 months. Power spectral analysis of heart rate variability showed very low power values at 1 month with inhibited cardiac autonomic activity and no response on sympathetic stress. A potential of recovery of cardiac autonomic activity was documented 12 months after surgery. CONCLUSIONS: The manifestations of sinus node dysfunction following the Cox-maze III procedure were time dependent and their frequency and intensity progressively decreased and disappeared within 12 months after surgery.

Regional diastolic dysfunction in postischaemic myocardium in calf: effect of nisoldipine.

OBJECTIVE: The aim was to assess the effect of nisoldipine on left ventricular systolic and diastolic function during prolonged myocardial ischaemia. METHODS: The left circumflex coronary artery was ligated for 2 h and reperfused for 4 h in 12 calves. The animals were randomised to a control group (n = 6) or to treatment with 1.25 mg.h-1 intravenous nisoldipine (n = 6) during 2 h of ischaemia. Circulatory support by a ventricular assist device was performed throughout the experiment except for the time of haemodynamic measurements. Regional wall thickening of a normal and an ischaemic left ventricular region was determined using pairs of ultrasonic crystals. Left ventricular pressure was measured by micromanometry. Left ventricular wall thickness and regional wall stiffness at a common preload of 10 mm Hg were calculated using an elastic model with shifting asymptote. RESULTS: Ten animals survived after 6 h. No difference was observed in systolic function between controls and nisoldipine treated animals. Systolic thickening of the ischaemic wall remained depressed 4 h after reperfusion and showed some recovery after dopamine infusion. Ischaemic wall stiffness at a common preload was lower after nisoldipine during ischaemia and reperfusion than in controls. Control wall stiffness remained unchanged during the whole experiment with and without nisoldipine. Diastolic thinning of the ischaemic wall was prevented by nisoldipine during ischaemia and after reperfusion. CONCLUSIONS: Prolonged myocardial ischaemia is associated with increased myocardial stiffness of the ischaemic wall. Mechanical unloading can help to bridge the acute phase but cannot prevent postischaemic diastolic dysfunction of the ischaemic wall. Nisoldipine has a beneficial effect on regional diastolic function during ischaemia and reperfusion by decreasing regional wall stiffness and preventing diastolic thinning of the ischaemic wall.

Interaction between some ergot alkaloids and the reactivity to dopamine of an identified neurone of Helix pomatia.

The effect of ergot alkaloids, some of them from the ergosine series, was tested on the response of an identified neurone of Helix pomatia to the application of dopamine (DA) which was membrane hyperpolarization (DA-I response). To evaluate the antagonistic potency of the ergot alkaloids, the dose-response relationship of the response to DA was established first in the absence and later in the presence of the tested compound. The sigmoidal dose-response curves obtained were used to determine the pA2 values of all the antagonists tested. Comparing them it was found that among the ergosines tested, the most potent was dihydroergosine, its pA2 value being (6.27) similar to the values obtained for dihydroergotoxine (6.66) and dihydroergotamine (6.36). The two other unhydrogenated compounds (ergosine and saccharinoergosine) had potencies of the same order as bromoergocryptine. The D-isomer (+) of the saccharino compound was the least potent, but it acted as a DA-receptor antagonists, as well as the dextroisomer of bromoergocryptine, bromoergocryptinine. By comparing the current-voltage relationship of the neurone in the presence and absence of the ergot alkaloids tested it was found that they had no non-specific effects on the membrane. The ergot alkaloids did not change the amplitude of depolarization of the neurone induced by gamma-aminobutyric acid (GABA) and acetylcholine (ACh).

The reaction of Helix photosensitive neurons to light and cyclic GMP.

The effect of light and cyclic nucleotides (cGMP and cAMP) on a group of identified photosensitive neurons in Helix pomatia left parietal ganglion was examined. The onset of light induces in these cells a slow inward current shift associated with decrement of slope conductance. The reversal potential (Erev) of the light induced current (IL) and its changes due to altered extracellular concentration of potassium support the assumption that (IL) is due to suppression of K+ conductance. Elevation of intracellular concentration of cyclic GMP by adding 8-bromo-cGMP into the bathing solution or by injecting the nucleotide into the cell mimics, in all cases, the effect of light: it produces an inward current accompanied by decrement of slope conductance. The effect of elevation of cAMP was inconsistent. The I-V relations of IL and IcGMP follow a similar course and have a common Erev. The assumption that 3',5'-cyclic GMP is increased by light is also supported by comparing the effect of light and the cyclic nucleotide on the action potential. Both light and 8-bromo-cGMP broaden the action potential by increasing the voltage-dependent Ca2+ current.

Ministernotomy versus complete sternotomy for coronary bypass operations: no difference in postoperative pulmonary function.

OBJECTIVES: Less-invasive approaches in cardiac operations offer certain cosmetic advantages, but it is unclear whether there are additional positive effects with regard to the postoperative recovery of patients. The aim of this prospective and randomized study was to ascertain whether partial inferior midline sternotomy can improve pulmonary function, one of the best quantifiable parameters of postoperative recovery, after coronary artery bypass operations when compared with the standard full midline approach. METHODS: One hundred patients scheduled for elective coronary artery bypass grafting were randomized either for a full median sternotomy (standard sternotomy group, n = 50) or for a partial inferior sternotomy (ministernotomy group, n = 50). The following pulmonary features were assessed: vital capacity, forced expiratory volume, percentage of forced expiratory volume from vital capacity, total lung capacity, residual volume, maximum inspiratory pressure, and maximum expiratory pressure. Tests were performed preoperatively and on the fourth and tenth postoperative days. RESULTS: On the fourth postoperative day, both groups had a significant decrease in vital capacity (percentage of predicted values) when compared with preoperative values (preoperative vs fourth day: standard sternotomy group, 87.8% +/- 14.3% vs 42.1% +/- 10.2% [P <.0001]; ministernotomy group, 84.5% +/- 14.3% vs 41.5% +/- 11.8% [P <.0001]), with a significant tendency for recovery from the fourth to the tenth postoperative day (fourth vs tenth postoperative day: standard sternotomy group, 42.1% +/- 10.2% vs 66.3% +/- 12.3% [P =.001]; ministernotomy group, 41.5% +/- 11.8% vs 61.3% +/- 13.1 % [P =.002]). There were no differences in any test results between the groups on either the fourth or the tenth postoperative day. CONCLUSION: A less-invasive approach for coronary artery bypass operations with a partial inferior sternotomy does not improve early postoperative pulmonary function when compared with the conventional approach with a full sternotomy.

Transcaval liver resection with hepatoatrial anastomosis for treatment of patients with the Budd-Chiari syndrome. Late results.

Between 1980 and 1990 transcaval liver resection with hepatoatrial anastomosis was performed in 17 patients with the Budd-Chiari syndrome. There were two early deaths (early mortality 11.7%). Hepatic function returned to normal and hepatosplenomegaly disappeared in all but two patients with preexisting cirrhosis. All survivors regained normal working capacity after the operation. During an average follow-up of 6 years (7 months to 11 years) there were three late deaths due to progression of the underlying disease. The actuarial 1-, 5-, and 10-year survivals were 82%, 76%, and 57%, respectively. Hepatoatrial anastomosis represents an optimal treatment for patients with the Budd-Chiari syndrome and obstruction of major hepatic veins. Patients with compression of the inferior vena cava, very common in this disease, were treated by simultaneous transcaval stenting. The late results are very satisfactory, with excellent quality of life. With adequate hepatic function, results of hepatoatrial anastomosis are superior to those of liver transplantation, which represents the only alternative for patients with the advanced form of the Budd-Chiari syndrome.

In situ repair of mycotic aneurysm of the ascending aorta.

Between 1969 and 1990 six patients (aged 14 to 64 years, mean 43 years) underwent in situ reconstruction for mycotic aneurysm of the ascending aorta. The primary source of infection was endocarditis in three patients (subacute bacterial endocarditis [n = one patient], sepsis with acute endocarditis [n = one patient]), sepsis with sternal osteomyelitis in one, sepsis with purulent pericarditis in one, and generalized febrile illness in one. In five of six patients the treatment consisted of the excision of changed tissue combined with a composite graft (n = one patient), a xenopericardial patch repair (n = one patient), a Dacron graft repair and aortic valve replacement (n = one patient), a Dacron graft repair alone (n = one patient), and a lateral suture combined with double valve replacement (n = one patient). In one patient with perforation of the mycotic aneurysm into the pulmonary artery, the place of rupture was oversewn without excision of the aortic or pulmonary artery tissue. Two patients with local pericardial inflammation were reoperated on during the hospital stay; one of them because of recurrent mycotic aneurysm of the ascending aorta at the other location and the other because of infection of the suture line after the Dacron patch repair. Antibiotic therapy was intravenously administered for 2 to 12 weeks postoperatively and continued orally for 4 to 8 weeks. The mean observation time was 6 years (range 4 months to 16 years). There was no late graft infection, except the chronic infection of the suture line in one patient who died suddenly 4 months after the operation. There was no early death, and there were three late deaths (chronic myocardial failure, one patient, chronic renal failure, one patient, sudden death, one patient). We concluded that in situ reconstruction for mycotic aneurysm of the ascending aorta combined with prolonged antibiotic therapy is an appropriate procedure with satisfactory early and good long-term results.

Aortic rupture and concomitant transection of the left bronchus after blunt chest trauma.

We report a patient with traumatic aortic rupture and preoperatively unrecognized complete disruption of the bronchus for the left lower lobe. Preoperative state was complicated by inadequate oxygenation due to total atelectasis of the unventilated collapsed left lower lobe with consequent significant shunting of the unoxygenated blood. The patient had no massive pneumothorax because the intact peribronchial tissue and pleura covered the injured place, preventing important air leakage. The suspicion of possible concomitant tracheobronchial injury and early diagnostic bronchoscopy are important in patients with aortic rupture after blunt chest trauma.

The Cox maze iii procedure: parallel normalization of sinus node dysfunction, improvement of atrial function, and recovery of the cardiac autonomic nervous system.

OBJECTIVE: The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure. PATIENTS AND METHODS: Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n = 12). RESULTS: The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function. CONCLUSION: Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system.

The influence of leukocyte filtration during cardiopulmonary bypass on postoperative lung function. A clinical study.

The accumulation of activated leukocytes in the pulmonary circulation plays an important role in the pathogenesis of lung dysfunction associated with cardiopulmonary bypass. Animal studies have demonstrated that the elimination of leukocytes from the circulation reduces postoperative lung injury and improves postoperative pulmonary function. We conducted a prospective randomized clinical study to evaluate whether postoperative lung function could be improved by use of a leukocyte filter during cardiopulmonary bypass. Elective coronary artery bypass grafting was done with a leukocyte-depleting arterial blood filter incorporated in the extracorporeal circuit (14 patients, leukocyte filter group) or without the filter (18 patients, control group). Blood samples collected at intervals before, during, and after operation were used for analysis of blood cell counts, elastase concentrations, and arterial blood gases. The use of the leukocyte filter caused no significant reduction in leukocyte count (p = 0.86). There were no differences in postoperative lung function between the groups, as assessed through (1) oxygenation index (290 for leukocyte filter group compared with 329 for control group, 95% confidence interval, 286 to 372, p = 0.21), (2) pulmonary vascular resistance (p = 0.10), and (3) intubation time (16.6 hours for leukocyte filter group versus 15.7 hours for control group, 95% confidence interval, 12.1 to 19.1 hours, p = 0.72). The levels of neutrophil elastase were significantly higher at the end of cardiopulmonary bypass in the leukocyte filter group (460 microgram/L in leukocyte filter group versus 230 microgram/L in control group, 95% confidence interval, 101 to 359 microgram/L, p = 0.003). We conclude that the clinical use of the present form of leukocyte-depleting filter did not improve any of the postoperative lung function parameters analyzed in this study.

A modified repair technique for tricuspid incompetence in Ebstein's anomaly.

OBJECTIVE: A modified technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. Midterm results of this therapeutic approach for patients with Ebstein's anomaly and tricuspid valve incompetence are reported. METHODS: Between October 1988 and April 1997, the incompetent tricuspid valve was repaired with our technique in 19 patients (12 female, 7 male; 2 to 54 years, mean 21 years). The indication for operation was congestive heart failure of various degrees in all patients. Tricuspid incompetence was grade II in two patients, grade III in 14, and grade IV in three. Associated congenital malformations were simultaneously repaired (interatrial communication in 18, ventricular septal defect in two, pulmonary stenosis in two, mitral valve prolapse in one). Follow-up ranged between 10 and 103 months (median 28 months) and was complete for all patients. RESULTS: There were no operative deaths. One patient with active endocarditis and pulmonary abscess died 2 months after the operation of recurrent sepsis; there were no late deaths. During follow-up, New York Heart Association functional class improved from 2.8 before the operation to 1.9 without recurrent cyanosis, and tricuspid incompetence decreased from a mean grade of 3.1 to one of 0.9, without any echocardiographic deterioration of the tricuspid valve function or right ventricular dilation. CONCLUSIONS: Our technique allows tricuspid valve repair in patients with Ebstein's anomaly, even in cases usually reserved for primary valve replacement, without late functional deterioration.

Prophylactic cytolytic therapy in heart transplantation: monoclonal versus polyclonal antibody therapy.

The value of immunoprophylaxis with monoclonal anti-CD3 antibodies (OKT3) was evaluated in 44 consecutive, nonrandomized heart transplant patients. The control group (n = 22) was treated with polyclonal rabbit antithymocyte globulin (RATG) for 5 days. The study group (n = 22) was treated with OKT3 for 14 days. All patients had identical perioperative immunosuppressive therapy and similar maintenance therapy, with cyclosporine, azathioprine, and low-dose prednisone (starting prednisone: OKT3 group immediately, RATG group 3 weeks [n = 11] or greater than 3 months [n = 11] after transplantation). The mean histologic rejection grade (Texas classification) in the RATG and the OKT3 groups was 2.5 +/- 1.9 and 0.6 +/- 0.8 (p less than 0.005) after 1 week and 4.3 +/- 1.6 and 2.0 +/- 1.5 (p less than 0.001) after 2 weeks, but there was no difference in the first year. The linearized rejection rate (rejections per 100 patient days) was higher in the RATG group in the first 2 weeks (2.6 vs 0, p less than 0.05 respectively, 7.8 vs 0.7, p less than 0.001) and higher in the OKT3 group in the second month (1.4 vs 2.8, p less than 0.01). In the RATG group the rejection rate fell continuously, to 0.1 at the end of the first year, whereas in the OKT3 group it remained 0.4 (NS). The cumulative first-year incidence was similar for persistent rejections (RATG 0.38 +/- 0.29 vs OKT3 0.48 +/- 1.13, NS) and insignificantly higher for severe rejections in the OKT3 group (RATG 0.21 +/- 0.32 vs OKT3 0.49 +/- 1.10). Rejection-related mortality in the first year was 0% (RATG) and 9% (OKT3).(ABSTRACT TRUNCATED AT 250 WORDS)

Implantation of antibiotic-releasing carriers and in situ reconstruction for treatment of mycotic aneurysm.

Four patients with mycotic aneurysm of the extracranial carotid artery, the innominate artery, the ascending aorta, and the infrarenal aorta were treated with local implantation of antibiotic-releasing carriers after resection of the aneurysm, excision of all infected tissue, and in situ reconstruction by prosthetic graft replacement in two patients and patch plasty in two patients. The patient with a mycotic aneurysm of the ascending aorta was operated on again 1 month after the first operation because of a second mycotic aneurysm located on the aortic arch. No early or late signs of recurrent infection were seen on clinical and laboratory postoperative follow-up done between 9 and 16 months or on duplex scan or computed tomography done at these times. Implantation of antibiotic-releasing carriers after débridement of all infected tissue and in situ reconstruction for treatment of mycotic aneurysm was performed successfully in four patients with this life-threatening condition.

Surgical treatment of a chest-wall penetrating left ventricular pseudoaneurysm.

This report describes the treatment of a patient who developed a chest-wall penetrating pseudoaneurysm 3 years after coronary bypass grafting and after the resection of a lateral wall left ventricular aneurysm twice. The patient presented with a pulsatile tumor in the left submammilar region. Surgery was done in deep hypothermia, with femoro-femoral cannulation and via a left anterolateral thoracotomy. The perioperative course was uneventful and the patient is still well 5 years after surgery.

Reoperations after operation on the thoracic aorta: etiology, surgical techniques, and prevention.

Recurrent aortic aneurysms, persistent or new dissection, new onset of valvular and coronary artery disease, graft infection, and prosthetic endocarditis are not rare after thoracic aortic operations; they can be difficult to diagnose and represent a formidable surgical challenge. Between 1977 and 1991, 876 operations were performed on the thoracic aorta in our institution: 340 in dissections, 299 in true aneurysms, 150 for aortic remodeling and external wall support during aortic valve replacement, and 87 for miscellaneous causes. During the same period, there were 193 additional reoperations. Vascular reoperations on abdominal aorta and peripheral arteries accounted for 73 cases and are not further discussed in this study. The reasons for reoperation (n = 130) in 120 patients were: failure of biologic valves (n = 23); aneurysm recurrence in a proximal or distal aortic segment (n = 21); pseudoaneurysm formation at suture lines (n = 13); new dissection or dilatation involving ascending aorta (n = 11), aortic arch (n = 13), and descending aorta (n = 10); aneurysm after aortic remodeling (n = 13); new onset of valvular disease (n = 5); and new onset of coronary disease (n = 5). Infected aortic graft and prosthetic endocarditis accounted for 10 reoperations, and a planned two-staged procedure was performed in 6 patients. Omitting the failed biologic valves, reoperations were performed on the aortic segment previously operated on in 69.3% of the cases and on other thoracic segments in 30.7%. Overall hospital mortality rate after reoperation was 5.8%. A significant decrease in operative mortality was observed in the most recent period (3.0% between 1989 and 1991). Reoperations are technically demanding, and some of them are preventable; therefore (1) graft inclusion technique should be abandoned in ascending aortic operation due to formation of false aneurysms; (2) in patients with Marfan syndrome, complete repair of the diseased aorta should be attempted during the initial operation; (3) aortic arch dissection should be repaired definitively during the first operation in low-risk patients; (4) biological valves should be avoided in aneurysm operations; and (5) homograft replacement is the treatment of choice in prosthetic endocarditis or in infected composite graft after an aortic valve or ascending aortic operation.

Hirudin as anticoagulant for cardiopulmonary bypass: importance of preoperative renal function.

BACKGROUND: Recombinant hirudin is an alternative anticoagulant for cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II. Although there is no neutralizing agent for recombinant hirudin, its fast renal elimination enables quick cessation of bleeding after cardiopulmonary bypass. The aim of the study was to compare anticoagulant effects of recombinant hirudin in regards to renal function in patients with heparin-induced thrombocytopenia type II. METHODS: Twenty-one patients (mean age, 65 years, and range, 35 to 82 years) underwent different complex cardiovascular procedures using recombinant hirudin as the anticoagulant for cardiopulmonary bypass. Postoperative blood loss, transfusion requirements, and hemostatic variables were compared between patients with a creatinine level lower than 1.5 mg/dL (group 1, normal renal function; n = 17 patients) and those with a creatinine level greater than 1.5 mg/dL (group 2, impaired renal function; n = 4 patients). RESULTS: The patients in group 1 showed no increased tendency toward postoperative bleeding. In contrast, all 4 patients in group 2 required reexploration for increased postoperative bleeding. They had higher activated partial thromboplastin times and transfusion requirements postoperatively. CONCLUSIONS: If recombinant hirudin is used as the anticoagulant for cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II and impaired renal function, the risk of postoperative bleeding is increased.