Use of "BioGlue" in aortic surgical repair.

A new bioadhesive (BioGlue, Cryolife Inc, Kennesaw, GA) was recently introduced for surgical use in thoracic aortic surgical repair. We describe our early experience and our suggested method of repair.

Maximal exercise testing for the selection of heart transplantation candidates: limitation of peak oxygen consumption.

BACKGROUND: Peak exercise oxygen consumption (peak VO2), which is considered an indicator of prognosis in advanced heart failure, is currently being used as a major criterion in many centers for the selection of candidates for heart transplantation. Available studies suggest that patients with peak VO2 < 14 mL/min/kg have improved survival and significant functional benefit with transplantation. Since patients may terminate symptom-limited exercise tests for a variety of reasons, peak VO2 does not necessarily reflect maximal VO2, leading to the possibility of inappropriate selection for transplantation. Therefore, we investigated the proportion of transplant candidates referred for exercise testing considered to have achieved maximal results from studies. METHODS: Fifty-five patients with heart failure, aged 51+/-9 years, (mean +/- SD) underwent maximum symptom-limited exercise tests on a cycle ergometer utilizing a Jones stage 1 incremental protocol. Tests were considered maximal if subjects achieved peak heart rate (HR) > 85% predicted ("cardiocirculatory limitation") or peak minute ventilation (VE) > 85% predicted ("ventilatory limitation"), and achieved an anaerobic threshold (AT) by noninvasive measures. RESULTS: Seven tests were terminated because of chest pain, ST-segment abnormalities, or ventricular arrhythmias. Of the remaining 48 studies, the reasons for stopping exercise were leg fatigue in 52%, dyspnea in 16%, and both symptoms in 23%. Sixteen of the 48 patients (33%) had peak VO2 < 14 mL/min/kg. In 8 of these 16 patients, both peak HR and VE were < 85% predicted. Of these eight without apparent HR or ventilatory limitation, none had oxygen desaturation below 90% or fall in BP, two were in atrial fibrillation, and only three had evidence that an AT was achieved. CONCLUSIONS: Among the patients with peak VO2 < 14 mL/min/kg, there were no objective signs of a cardiocirculatory or a respiratory limitation to exercise in half of them, and 31% did not achieve an AT either, thus not meeting any criteria to support evidence of maximal exercise. Exercise tests without objective evidence of cardiocirculatory or ventilatory limitation may not represent maximal performance. Consequently, peak VO2 may misclassify an appreciable proportion of candidates if the test results are submaximal. CLINICAL IMPLICATIONS: Clinical exercise studies indicating low peak VO2 must be interpreted in the context of whether a defined objective exercise limitation is evident to avoid biasing the selection of heart transplant candidates.

Pentastarch versus albumin in cardiopulmonary bypass prime: impact on blood loss.

BACKGROUND: Albumin is commonly used as a volume expander in cardiopulmonary bypass (CPB) prime. Pentastarch, a low molecular weight hetastarch, may provide similar efficacy at decreased cost but is known to alter coagulation profiles. Infectious concerns forced the temporary withdrawal of albumin in our institution. Therefore we evaluated pentastarch as an alternative with regards to perioperative hemostasis and blood loss. METHODS: One hundred consecutive adult patients undergoing first-time aorto-coronary bypass were given 750 mL of 10% pentastarch (represented as P in calculations) diluted in 1000 mL of Ringer's solution added in their CPB prime. A similar control group of 100 consecutive patients had received 200 mL of 25% albumin (represented as A in calculations) diluted in 1500 mL of Ringer's solution. RESULTS: Postoperative prothrombin time (PT) was slightly higher with pentastarch (P: 14.9 +/- 1.5 seconds, A: 14.2 +/- 1.3 seconds, p = 0.003). Postoperative bleeding was also increased (P: 2337 +/- 1242 mL, A: 1981 +/- 1121 mL, p = 0.034), mostly because of recirculated shed mediastinal blood (P: 834 +/- 499 mL, A: 640 +/- 388, p = 0.002) rather than lost pleural tube blood (P: 1503 +/- 821 mL, A: 1341 +/- 824 mL, p = 0.16). Overall net blood loss (P: 2014 +/- 914 mL, A: 2061 +/- 1015, p = 0.73) was similar. Blood-product transfusion requirements and postoperative daily hematocrits did not differ. CONCLUSION: The diminished coagulability associated with this dose of pentastarch resulted in increased postoperative bleeding. However, with recirculation of shed mediastinal blood, there was no net increase in blood loss. In this setting, pentastarch may serve as a suitable alternative to albumin.

Transplantation versus coronary artery bypass in patients with severe ventricular dysfunction. Surgical outcome and quality of life.

BACKGROUND: The purpose of this study is to evaluate the quality of life, functional status and survival rate of patients with left ventricular ejection fraction (LVEF) < or = 20% following coronary bypass (CABG) versus heart transplantation. EXPERIMENTAL DESIGN: comparative study, mean follow-up of 20 months. SETTING: division of cardiac surgery at a McGill University-based hospital in Montreal, Canada. PATIENTS: the charts of 65 consecutive patients with angiographic LVEF < or = 20% were reviewed. Among these patients, 14/65 were referred for transplantation but instead underwent CABG (Group I) after consultation with the transplant committee. The charts of 14 matched transplant patients (Group II) were reviewed. The SF-36 and Duke's questionnaire forms were mailed to both groups in order to evaluate their quality of life and functional capacity, respectively. INTERVENTIONS: comparison between coronary bypass and heart transplantation. MEASURES: main outcome measures were mortality, quality of life, and functional capacity. RESULTS: Results are expressed as mean+/-SEM. The in-hospital mortality rate of CABG among all patients with LVEF < or = 20% was 4.6% (3/65). Among the 14 CABG patients initially referred for transplantation, perioperative mortality was 1/14 (7.1%), same as in the matched transplant group. Three additional group I patients were reported by family to have died of cardiac events at follow-up period. Postoperative death identified at follow-up was assigned the lowest life quality score. The transformed quality of life scores were as follows: physical functioning: I=42.5+/-10.6, II=73.2+/-7.2, p=0.029; physical role: I=35.0+/-13.5, I=61.4+/-13.2, p=0.180; bodily pain: I=54.0+/-14.0, II=69.8+/-8.5, p=0.349; general health: I=34.7+/-9.2, II=84.6+/-5.2, p=0.0003; vitality: I=36.5+/-9.3, II=60.0+/-5.2, p=0.045; social functioning: I=55.0+/-4.0, II=87.5+/-5.1, p=0.050; emotional role: I=36.7+/-15.3, II=87.9+/-6.8, p=0.009; mental health: I=52.8+/-12.4, II=81.5+/-4.2, p=0.054. Duke's activity status index: I=16.8+/-4.2, II=31.8+/-4.2, p=0.021. CONCLUSIONS: Heart transplant is associated with a significantly superior postoperative quality of life and functional capacity than bypass surgery. However, in patients with LVEF < or = 20%, CABG can be performed with an acceptable perioperative mortality of 4.6%-7.1%, similar to the rate for transplantation.

Efficacy and side-effects of cyclosporine dose monitoring with levels 6 h after the morning dose in heart transplant patients.

The purpose of this study was to compare CsA dose monitoring with trough levels (T0) vs. levels obtained 6 h after the morning dose of CsA (T6), with respect to the incidence of acute rejection and renal dysfunction, and the cumulative dose, as well as the cost of CsA after heart transplantation. Twenty consecutive adult heart transplant patients receiving quadruple sequential immunosuppression were prospectively randomized into CsA monitoring with T0 (Group I) vs. T6 levels (Group II). Oral CsA was started at a dosage of 2 mg/kg/d, 1-4 d after transplantation. The target range for either T0 or T6 was 150 to 250 ng/ml (enzyme multiplied immunologic technique), respectively. The CsA dose was increased or decreased by 0.5-1 mg/kg/d if the measured level was outside of the target range. Throughout the follow-up period (Group I, 11 +/- 2 months; Group II, 10 +/- 3 months), the incidence of acute rejection (ISHLT grade > or = 2) was 50% in each group. The left ventricular ejection fraction and serum creatinine were similar in both groups at 1 month and at the end of the follow-up. The maximal dose of CsA (mg/kg/d): 3.8 +/- 1 vs. 5 +/- 0.6 (P = 0.002), the minimal dose: 2.2 +/- 0.7 vs. 3.4 +/- 0.8 (P = 0.003), and the current dose: 2.6 +/- 0.6 vs. 3.5 +/- 1 (P = 0.02), were lower in Group II, as well as the cumulative dose of CsA (mg): 61,790 +/- 19,754 vs. 88,524 +/- 18,082 (P = 0.005), and its cost (CDN$): 3,589 +/- 1,116 vs. 5,106 +/- 1,045 (P = 0.005). In conclusion, CsA dose monitoring with T6 was associated with a 30% lower CsA dose and cost compared to T0, with the same effectiveness in the prevention of acute rejection, and similar cardiac and renal function.

Treatment of steroid-resistant and recurrent acute cardiac transplant rejection with a short course of antibody therapy.

The purpose of this study was to assess the efficacy of short courses of OKT3 and ATG, respectively, for steroid resistant or recurrent acute allograft cardiac rejection (AR). Between June 1988 and March 1994, 101 heart transplant patients were treated with a quadruple sequential immunosuppression protocol (ATG, azathioprine, CsA, and prednisone). AR was diagnosed by endomyocardial biopsy (EMB), and patients with scores > 2 (ISHLT) received pulse methylprednisolone, 500 mg i.v. on 3 consecutive days. In cases of steroid-resistant or recurrent AR, OKT3 (5 mg/d) or ATG (1.5-2.5 mg/kg/d), was administered for 5-7 d instead of the usual 10-14 d course. OKT3 (17 courses; 10 steroid resistant, 7 recurrent AR; 5.3 +/- 0.7 doses) was given to 16 patients (4F/12M, 45 +/- 11 yr), 29-269 d after transplantation. ATG (8 courses; 5 steroid resistant, 3 recurrent AR; 4.9 +/- 0.6 doses) was given to 8 patients (1F/7M, 53 +/- 7 yr), 23-503 d after transplantation. Successful treatment of AR with a score < 2 at the first and second EMB after treatment was 88% and 88% with OKT3, and 87.5% and 100% with ATG, respectively. Throughout follow-up (50 +/- 22 months after OKT3; 49 +/- 28 months after ATG), there was a trend towards lower incidence of subsequent AR after ATG (25% vs. 69%, P = 0.09), and similar incidence of infections, graft atherosclerosis and mortality. No cases of lymphoproliferative disorder were observed. We conclude that short courses of OKT3 or ATG are safe and effective for the treatment of steroid resistant or recurrent AR, with a similar incidence of complications. These results may have cost-effectiveness implications and need to be confirmed in a randomized study.

Impact of transfusion of mediastinal shed blood on serum levels of cardiac enzymes.

BACKGROUND: Infusion of shed mediastinal blood using an autotransfusion system is a widely applied technique of blood conservation in cardiac surgery. Serial determinations of serum creatine kinase (CK), its MB isoenzyme (CK-MB), and lactate hydrogenase (LDH) levels have been used to monitor perioperative myocardial injury. We investigated the impact of postoperative autotransfused blood infusion on serum levels of these enzymes. METHODS: We performed a retrospective analysis of postoperative serum CK, CK-MB, and LDH levels of 300 patients who had elective uncomplicated aortocoronary bypass grafting. Shed mediastinal blood samples from 26 patients were analyzed for CK, CK-MB (enzymatic activity and mass), and LDH levels before infusion. RESULTS: High postoperative serum levels of CK and LDH were observed after infusion of autotransfused blood. Shed mediastinal blood contained extremely high levels of these enzymes, particularly from patients who had internal mammary artery dissection. There was a strong correlation (r = 0.96) between measured CK-MB enzyme activities and those calculated from the CK-MB mass units. CONCLUSIONS: Infusion of autotransfused blood containing high concentrations of CK and LDH results in elevated serum levels of these enzymes. Hemolysis, frequently present in shed blood, does not interfere with the routine biochemical assays for CK and CK-MB enzyme activities. Caution should be taken when postoperative cardiac enzyme levels are used to determine myocardial injury after aortocoronary bypass grafting if autotransfusion is used as a method of blood conservation.

Carotid artery duplex scanning in preoperative assessment for coronary artery revascularization: the association between peripheral vascular disease, carotid artery stenosis, and stroke.

PURPOSE: The purpose of this study was to identify high-risk populations for severe carotid artery disease (SCD) and neurologic events (NE) after nonemergency isolated coronary artery bypass graft procedures (CABG). METHODS: Between February 1989 and July 1992, 387 patients underwent preoperative carotid artery duplex scanning as part of a preoperative assessment for nonemergency cardiac procedures. Of these patients, 376 had isolated CABG, and 11 had combined carotid endarterectomy (CEA) and CABG. Patient demographics, risk factors, and preoperative neurologic symptoms were recorded and analyzed. Severe carotid artery disease was defined as a 80% or greater stenosis of either internal carotid artery by carotid artery duplex scanning. Patients were evaluated for neurologic events (cerebrovascular accident, transient ischemic attack, amaurosis fugax, or reversible ischemic neurologic deficits) during the in-hospital postoperative period. RESULTS: The prevalence of SCD was 8.5% (33 patients). The 33 patients with SCD were significantly older (65.6 +/- 6.5 years vs 62.5 +/- 10.4 years, p = 0.02), had previous CEA (27.3% vs 2.0%, p = 0.00001), had preoperative neurologic symptoms (21.2% vs 5.9%, p = 0.002), and had peripheral vascular disease (PVD) (63.6% vs 16.9%, p = 0.00001). The sensitivity of PVD for SCD is 63.6% (n = 21/33) (specificity 83.1%, positive predictive value 25.9%, negative predictive value 96.1%). In patients undergoing CABG alone, those who had postoperative NE were older (69.6 +/- 6.7 years vs 62.5 +/- 10.3 years, p = 0.036) and more likely to have PVD (50% vs 19.7%, p = 0.034), SCD (40% vs 4.9%, p = 0.001) and previous CEA (40% vs 2.7%, p = 0.0002). The incidence of postoperative NE in patients with SCD was 18.2% vs 1.7% in patients without SCD (p = 0.001). The sensitivity of SCD for NE was 40% (n = 4/10) (specificity 95.1%, positive predictive value 18.2%, negative predictive value 98.3%). CONCLUSIONS: PVD may be helpful to identify patients at high risk for severe carotid artery stenosis. Postoperative NE in patients with CABG are associated with increasing age, carotid artery stenosis greater than 80%, previous CEA, and PVD.

Current surgical management of tetralogy of Fallot.

The surgical management of tetralogy of Fallot has undergone important changes in recent years. Earlier repair of tetralogy of Fallot is now favored by many institutions. At Stanford University Medical Center, we have performed definitive repair of tetralogy of Fallot at the time of presentation, regardless of the child's age, with few exceptions. In this report, we describe our results with early repair, and we believe these support the contention that infants who undergo early repair (< 1 year of age) have postoperative results similar to those of children who undergo repair at an older age. Complications related to shunts are prevented by the infant repairs, and, in the future, reduced ventricular ectopy may be demonstrated to be a benefit of such repairs.

Norwood operation for univentricular heart with subaortic stenosis in the neonate.

In the setting of a single ventricle, subaortic stenosis may be enhanced by pulmonary artery banding and may later contraindicate a Fontan operation. The Norwood operation may prove a preferable alternative in some infants as a preparatory procedure. We have successfully used this procedure as the initial operation to palliate a newborn with tricuspid atresia, transposition of the great arteries, coarctation, and severe arch hypoplasia secondary to a restrictive bulboventricular foramen.

Internal carotid artery aneurysm and Marfan's syndrome.

Aneurysms of the extracranial carotid artery are most commonly caused by atherosclerosis or trauma but may also have unusual causes, such as Marfan's syndrome. Although aneurysmal changes in the extracranial carotid vessels usually are due to extension of aortic dissection into the carotid system, isolated aneurysms may occasionally complicate Marfan's syndrome. The authors report a case of Marfan's syndrome in which the patient, a 45-year-old woman, presented with an asymptomatic mass in the right side of the neck at the level of the carotid bifurcation. An isolated internal carotid artery aneurysm was identified. The aneurysm was resected using an interposition vein graft over an outlying shunt. Histologic examination confirmed the typical cystic medial necrosis with loss of elastic fibres and an increase of mucoid material in the media. The patient's recovery was smooth and at 2-year follow-up there were no signs of recurrent aneurysm formation.

Altered leukocyte delivery to specific and nonspecific inflammatory skin lesions following burn injury.

This study assessed the effect of burn trauma on the in vivo leukocyte cell delivery during the first 24 hr of the delayed type hypersensitivity (DTH) skin test reaction and a bacterial skin abscess. Inbred male Lewis rats sensitized to keyhole limpet hemocyanin (KLH) were given a 30% scald burn or sham burn. Three days later the animals were injected intradermally, at different sites, with 0.3 mg of KLH, 10(8) organisms of S. aureus 502A, and 0.1 cc of saline, at 2 to 24 hr. Leukocytes labelled with Indium111 oxine(leu111) were injected intravenously. In sham rats the peak leu111 influx in the DTH reaction occurred at 2-4 hr while in the abscess it was biphasic with peaks at 3 hr and 6-8 hr. In burn trauma rats there was a markedly increased leu111 peak at 2 hr in both the DTH and abscess reactions followed by a significantly lower than normal leu111 delivery in the late (6-24) hours. This marked early leukocyte influx in burned rats was paralleled by a reduced DTH skin test lesion (8.2 +/- 1.1 mm to 4.2 +/- 1.1 mm) and an increased bacterial abscess (5.1 +/- 1.1 mm to 8.1 +/- 0.9 mm) post burn. There was a direct correlation between leukocyte cell delivery to a DTH reaction and a bacterial abscess (r8 = 0.69, Spearman rank; p less than 0.001). We conclude that burn trauma results in altered leukocyte delivery to inflammatory lesions and the DTH response can be used to assess the ability of a burn trauma host to recruit leukocytes at a site of infection.

The influence of long-term protein deprivation on in vivo phagocytic cell delivery to inflammatory lesions.

The effect of long-term protein deprivation and refeeding was assessed on the in vivo delivery of phagocytic leukocytes (PHAGS) to delayed-type hypersensitivity (DTH) reaction and a bacterial abscess. Male inbred Lewis rats sensitized to keyhole limpet hemocyanin (KLH) were fed either a normal diet or a 2% protein diet for 1, 6, and 10 weeks. Two additional groups were fed a 2% protein diet for 10 weeks but were refed with a normal diet for 1 or 4 weeks. At the end of each diet period rats were injected intradermally with KLH, Staphylococcus aureus 502A, and saline solution at different sites at from 1 to 24 hours. Technetium-99m-colloid labeled PHAGS (99PHAG) were injected intravenously and used to assess in vivo PHAG cell delivery. In normally fed rats the peak influx of 99PHAG was at 2 to 4 hours. After 1 week of protein-deficient diet there was a significant drop in early (2 to 4 hours) 99PHAG influx to both the DTH and bacterial reactions. After 10 weeks of protein deprivation (severe malnutrition) there was a further drop and a delay in the peak 99PHAG influx (from 2 to 4 hours, to 8 hours). A return to normal 99PHAG influx occurred only after 4 weeks of refeeding, and it coincided with a return to normal body weight and a normal DTH reaction. There was a direct correlation between total 99PHAG delivery to a DTH reaction and a bacterial abscess (rs = 0.87, Spearman rank; p less than 0.001). We conclude that both moderate and severe protein deprivation is associated with reduced in vivo phagocytic cell delivery to both a DTH reaction and a bacterial skin abscess, which can be restored with refeeding.

The effect of indomethacin on burn-induced immunosuppression.

Recent interest in the role of prostaglandin inhibitors as immunomodulators following major injury prompted us to study the effect of indomethacin on burn-induced immunosuppression in rats as measured by the delayed-type hypersensitivity (DTH) skin test response, ability to contain an intradermal bacterial challenge (10(8) Staphylococcus aureus 502A injected intradermally), and overall survival from spontaneous burn wound sepsis. Fifty male Sprague-Dawley rats sensitized to keyhole limpet hemocyanin (KLH) were subjected to a 30% full-thickness scald burn. Group 1 (n = 24) received indomethacin at 0.5 mg/kg intraperitoneally once daily with the first dose given immediately following the burn. Group 2 (n = 24) received vehicle only. Prostaglandin E2 measured by radioimmunoassay on day 17 was 2553 +/- 832 pcg/ml serum (+/- SEM) in the vehicle group and 1042 +/- 231 pcg/ml in the indomethacin group (P = 0.058, unpaired t test). Burn injury induced a decrease in the DTH response to KLH and an increase in the Staph lesion size (P less than 0.05) which was not corrected by indomethacin treatment. All animals developed spontaneous burn wound sepsis by day 14. Survival after 17 days in the indomethacin group was 100% compared to that of the vehicle group, 79%, P less than 0.05 (Fisher exact test). We conclude that despite unmeasurable corrections of the burn-induced suppression of the DTH response and local nonspecific bacterial defenses, low-dose indomethacin improves survival following burn sepsis.

In vivo and in vitro humoral immunity in surgical patients: antibody response to pneumococcal polysaccharide.

We have previously shown that the antibody response to a T cell-dependent protein antigen, tetanus toxoid is reduced in patients having surgery. Because most bacterial antigens are not protein but polysaccharide, we studied in vivo and in vitro antibody responses to a relatively T cell-independent polysaccharide antigen, 23 valent pneumococcal polysaccharide (Pneumovax) (PPS). Subjects were classified by skin testing with five standard antigens as reactive patients (R, positive response to any antigen, N = 5), anergic patients (A, no response, N = 7) or laboratory controls (C, reactive personnel, N = 8). Blood lymphocytes taken before and after immunization with 0.5 ml PPS were cultured in vitro. Quantities of total and anti-PPS IgG, IgM, and IgA in culture supernatants and serum were measured by radioimmunoassay. There was no difference in in vivo anti-PPS production in the three groups (p greater than 0.05 for all comparisons, Wilcoxon rank-sum test). Positive response rates (greater than twofold increase) for all classes of immunoglobulin were also similar in the three groups (X2(2) = 0.36, 0.36, and 0.81 for IgG, IgM, and IgA, p greater than 0.05). In in vitro studies, peak quantities of IgA anti-PPS produced by A were significantly less than C (0.64 X divided by 0.41 versus 2.03 X divided by 0.6, p less than 0.05, Wilcoxon rank-sum test). Synthesis of all other classes of Ig anti-PPS and simultaneous measurement of total Ig (nanograms per culture) produced in vitro were not significantly different among all groups (p greater than 0.05, Wilcoxon rank-sum test). In C, R, and A, peak in vitro isotype-specific anti-PPS production correlated with the magnitude of the in vivo serum response (Spearman rank correlation = 0.53, 0.60, and 0.59 for IgG, IgM, and IgA, p less than 0.05). We conclude that these data show normal in vivo antibody responses to a relatively T cell-independent bacterial polysaccharide antigen in surgical patients and a good correlation of in vivo- to in vitro-specific antibody responses. The data imply that a T cell defect is responsible for reduced humoral immunity to protein antigens. Because most bacterial antigens are not protein but polysaccharides, active immunization of patients with bacterial vaccines may produce effective immunity.