Biomedical subjects

D E Cameron

Publications and source records attributed to D E Cameron.

At least 55 records · Page 3Linked to original sources

PubMed1994

Mitral valve operation in patients with the Marfan syndrome.

Optimal surgical treatment of mitral regurgitation in the Marfan syndrome (valve repair versus replacement) is controversial because the underlying connective tissue defect theoretically might compromise repair durability. To examine the results of mitral valve repair in these patients, we did a retrospective review of 160 patients with the Marfan syndrome who had cardiac surgical procedures between January 1983 and January 1993. Thirty-six patients had mitral procedures, 29 of which were repairs. Mitral valve replacement was necessary in seven patients because of extensive annular calcification and/or severe anterior leaflet abnormalities. The 18 men and 11 women undergoing mitral valve repair had a mean age of 26.5 +/- 2.6 years (range 9 months to 54 years); seven patients were less than 18 years of age. Twenty-four of the 29 patients had concomitant aortic root replacement because of aortic dilation or valvular insufficiency. All 29 repairs included annuloplasty, and 11 patients also required leaflet resection. There were no operative deaths. At mean follow-up of 26.6 +/- 4.8 months, there have been three late deaths, two caused by arrhythmia and one by complications of type III aortic dissection. All survivors are in New York Heart Association class I or II. In three patients recurrent mitral regurgitation developed (grade III or IV); 5-year actuarial freedom from significant mitral regurgitation was 88.3%. One patient required repeat mitral annuloplasty after endocarditis of the composite aortic graft spread to the mitral valve. No patient required late mitral valve replacement. These results demonstrate that (1) 22% of patients with the Marfan syndrome who undergo cardiac operation require a mitral valve procedure, (2) most can be treated by mitral repair rather than replacement, and (3) at early follow-up, results of mitral repair in this population are satisfactory.

Actuarial Analysis↗

PubMed1994

Glutamate excitotoxicity: a mechanism of neurologic injury associated with hypothermic circulatory arrest.

Glutamate, the major central nervous system neurotransmitter, may have potent neurotoxic activity under conditions of metabolic stress. By receptor autoradiography, we have demonstrated that brain regions most vulnerable to injury during prolonged hypothermic circulatory arrest have the highest density of glutamate receptors. To test the hypothesis that such injury could be mediated by glutamate excitotoxicity, we used dizocilpine (MK-801), a selective N-methyl-D-aspartate-glutamate receptor antagonist in a canine survival model of hypothermic circulatory arrest. Eighteen male dogs (20 to 25 kg) were supported by closed-chest cardiopulmonary bypass, subjected to 2 hours of hypothermic circulatory arrest at 18 degrees C, and rewarmed on cardiopulmonary bypass. All were mechanically ventilated and monitored for 20 hours before extubation and survived for 3 days. Group A dogs (n = 9) received a prearrest intravenous bolus of dizocilpine (0.75 mg/kg) followed by continuous infusion (75 micrograms/kg per hour), resulting in electroencephalographic silence. Dizocilpine was weaned before extubation. Group B dogs received vehicle only. According to a species-specific behavior scale that yielded a neurologic deficit score ranging from 0 (normal) to 500 (brain dead), all animals were neurologically assessed every 12 hours. After the dogs were killed at 72 hours, brains were examined by receptor autoradiography and histologically for patterns of selective neuronal necrosis; they were scored blindly from 0 (normal) to 100 (severe injury). Group A dogs had better neurologic function than group B (neurologic deficit score 21 +/- 15 versus 192 +/- 40, p < 0.001) and had less neuronal injury (7.3 +/- 3 versus 48.3 +/- 9, p < 0.0001). Densitometric receptor autoradiography revealed preservation of neuronal N-methyl-D-aspartate-glutamate receptor expression in group A only. These results represent the first direct evidence of a role for glutamate excitotoxicity in the development of hypothermic circulatory arrest-induced brain injury and suggest that selective glutamate receptor antagonists may have a neuroprotective capacity in prolonged periods of hypothermic circulatory arrest.

Animals↗

PubMed1993

Neutrophil activation mediates protamine-induced pulmonary hypertension.

Protamine reversal of heparin anticoagulation can cause catastrophic pulmonary hypertension, systemic hypotension, and hypoxemia. This reaction is thought to be associated with pulmonary sequestration of activated neutrophils. To examine whether this reaction could be prevented by blocking neutrophil activation with NPC 15669 (N-(9H-(2,7-dimethylfluorenyl-9-methoxy)carbonyl)-L-leucine), an inhibitor of Mac-1 adhesion molecule up-regulation, we gave 12 piglets a heparin bolus (300 IU/kg i.v.) followed by protamine (3 mg/kg i.v. over 90 sec) 15 min later. Six of the piglets received NPC 15669 (10 mg/kg i.v. bolus, then 6 mg/kg/hr i.v. infusion) 15 min before the heparin bolus. Two minutes after protamine administration, CD18 (beta-subunit of Mac-1) expression measured by immunofluorescence flow cytometry increased 128 +/- 9% (mean +/- SEM) over preprotamine levels in control piglets but remained unchanged in NPC piglets (99 +/- 2%, P < 0.05). Fifteen minutes after protamine, lung myeloperoxidase activity, an index of neutrophil degranulation, was significantly lower in the NPC group (87.83 +/- 10.04 versus 57.23 +/- 2.59 mumol/10 mg; P < 0.005). NPC 15669 also prevented postreversal pulmonary artery hypertension (158 +/- 30, 150 +/- 20, and 140 +/- 13 versus 91 +/- 7, 91 +/- 18, and 85 +/- 9% preprotamine at Minutes 2, 5, and 10; P < 0.05). Systemic arterial pressure, cardiac output, and circulating neutrophil counts were not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Biomechanical study of sternal closure techniques.

Median sternotomy is the most commonly used incision in cardiothoracic surgery. Closure of this incision is usually performed with parasternal wires, but alternate techniques have been proposed to improve closure stability. This study compares biomechanical stability of standard wire (No. 5 stainless steel) with that of three types of band closure: 5-mm Mersilene ribbon, 5-mm stainless steel band, and 5-mm plastic band. Eight bisected cadaver sterna were reapproximated using each method of sternal fixation and tested for biomechanical stability using an MTS Bionix 858 Biomechanical Tester. Loads of 50, 100, 150, and 200 Newtons (1 Newton = 1 kg.m/s2) were applied as a distracting force across the closure. A linear regression line of displacement as a function of increasing load was determined for each closure method; the slope of this line is inversely proportional to fixation stability. Displacement and load correlated linearly for each closure (r = 0.99). Mean slopes were 0.012 mm/Newton (95% confidence limits, 0.0098 to 0.0142 mm/Newton) for No. 5 stainless steel wire, 0.014 mm/Newton (95% confidence limits, 0.0118 to 0.0162 mm/Newton) for plastic band, 0.017 mm/Newton (95% confidence limits, 0.0148 to 0.0192 mm/Newton) for Mersilene ribbon, and 0.017 mm/Newton (95% confidence limits, 0.0148 to 0.0192 mm/Newton) for 5-mm steel band. No. 5 stainless steel wire provided the most stable closure, although statistical significance was achieved only in comparison with Mersilene ribbon and stainless steel band (p < 0.05). The superior stability of stainless steel wire closure may be due to tightening of the wires by twisting, which results in more tension across the reapproximated sternal halves than with other methods.

Biomechanical Phenomena↗

PubMed1993

Neutrophil adhesion molecule expression during cardiopulmonary bypass with bubble and membrane oxygenators.

The neutrophil-mediated tissue injury associated with cardiopulmonary bypass (CPB) is thought to require the interaction of specific neutrophil and endothelial adhesion molecules. In this study, the effects of CPB on the expression of neutrophil CD11b and CD18 (the components of the Mac-1 adhesion molecule) were examined; the effects of membrane versus bubble oxygenators on the expression of neutrophil CD11b and CD18 were compared; and the plasma levels of the intercellular adhesion molecule-1 (cICAM-1), an inducible endothelial adhesion molecule, were measured. In addition, the time courses of complement activation and neutrophil granule release were measured to determine their temporal relationship to the expression of the neutrophil adhesion molecule. Fifteen adult patients underwent procedures requiring cardiopulmonary bypass; hollow-fiber membrane oxygenators were used in 8 (group M) and bubble oxygenators were used in 7 (group B). Blood samples were drawn before, during, and after CPB for determination of the expression of neutrophil CD11b and CD18 (immunofluorescent flow cytometry), and the plasma cICAM-1, elastase, lactoferrin (enzyme-linked immunoabsorbent assay), and plasma C3a (radioimmunoassay) levels. CPB caused an immediate and sustained increase in the neutrophil CD11b and CD18 expression in both groups; after 60 minutes of CPB, CD11b expression had increased by 116.9% +/- 19.1% in group B and by 79.3% +/- 8.5% in group M (p = 0.78). Over the same period, CD18 expression increased by 97.2% +/- 17.9% in group B and by 72.4% +/- 16.8% in group M (p = 0.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Leukocyte depletion in a neonatal model of cardiac surgery.

Neonatal cardiac surgical procedures continue to be associated with a considerable incidence of severe post-operative ventricular dysfunction. The role of neutrophils in mediating such injury has recently been proposed but remains controversial. The present study was undertaken to examine the potential benefits of leukocyte depletion for myocardial preservation using an in situ, in vivo porcine model of neonatal cardiac surgery. Sixteen 3- to 5-day-old piglets, 8 controls and 8 leukocyte-depleted animals (LD group), underwent 90 minutes of hypothermic ischemia. Mechanical leukocyte filtration during cardiopulmonary bypass reduced the granulocyte count in the initial reperfusate to 0.7% of controls. This was associated with a reduction in leukocyte sequestration in the coronary vascular bed (p < 0.005), a decrease in myocardial creatine kinase release (p < 0.02), and a reduction in coronary vascular resistance (p < 0.03). These changes in physiological response to ischemia were associated with improved postischemic recovery of left ventricular systolic function in LD animals (p < 0.05), although there was no significant improvement in diastolic function. Application of this technique in neonatal cardiac operations may improve myocardial protection and reduce the associated morbidity and mortality.

Animals↗

PubMed1993

Heparin-coated bypass circuits reduce pulmonary injury.

Heparin coating of the extracorporeal circuit not only reduces heparin requirements during cardiac operations but also may reduce organ injury associated with cardiopulmonary bypass (CPB). To examine this possibility, pulmonary injury and neutrophil adhesion molecule expression after CPB were studied in pigs undergoing CPB with a standard extracorporeal circuit (group S, n = 6) or a heparin-coated CPB circuit (Carmeda BioActive Surface) (group HC, n = 6). Pigs received heparin sodium (300 U/kg intravenously) and then underwent 90 minutes of hypothermic (28 degrees C) CPB using membrane oxygenators, followed by 2 hours of observation. Blood samples were obtained for determination of neutrophil number and expression of the neutrophil adhesion molecule subunit CD18 (by immunofluorescence flow cytometry). The CPB-associated injury was less in group HC. Two hours after CPB, the arterial oxygen tension group was higher in group HC (597.2 +/- 31.2 versus 220.5 +/- 42.3 mm Hg; p < 0.0001), the pulmonary vascular resistance was lower in these animals (408.6 +/- 69.4 versus 1,159.8 +/- 202.4 dyne.s.cm-5; p = 0.02), and the static compliance was higher in group HC (66.4 +/- 5.4 versus 39.8 +/- 5.8 mL/mm Hg; p = 0.004). After 60 minutes of CPB, both groups had similar increases in expression of the neutrophil adhesion molecule subunit CD18 (29.4% +/- 19.5% versus 26.0% +/- 24.4%, group S and group HC, respectively) and similar decreases in neutrophil counts (6,056 +/- 1,285 to 2,453 +/- 979 cells/microL versus 6,010 +/- 1,748 to 3,197 +/- 1,225 cells/microL, group S and group HC, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Valvular disease in the elderly: influence on surgical results.

Aortic valve disease in the elderly is primarily calcific stenosis with preservation of left ventricular function. In contrast, mitral valve disease in the elderly often is ischemic in nature with damage occurring to both valve and myocardium. The present study was undertaken to compare results of aortic (AVR) and mitral valve replacement (MVR) in the elderly and to ascertain predictors of poor outcome. Because patients who had concomitant coronary artery bypass grafting (CABG) are included (51% for AVR, 55% for MVR), patients who had isolated CABG were used as a comparison group. Between January 1, 1984, and June 30, 1991, 1,386 patients aged 70 years and older underwent CABG (n = 1,043), AVR (n = 245), or MVR (n = 98). The operative mortality rates were 5.3% for AVR, 20.4% for MVR, and 5.8% for CABG. Late follow-up of patients undergoing operation in 1984 and 1985 was available for 98% (231/237). Overall survival was comparable for all three groups through the first 5 years of follow-up (AVR, 68% +/- 8%; MVR, 73% +/- 8%; CABG, 78% +/- 3%). After 5 years, survival for patients having AVR and MVR was less than that for those having CABG. Patient age, sex, New York Heart Association functional class, concomitant CABG, prosthetic valve type, native valve pathology, and preoperative catheterization data were examined as possible predictors of outcome by multivariate logistic regression.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1993

Inhibition of neutrophil adhesion reduces myocardial infarct size.

Neutrophil accumulation and activation within the myocardium during ischemia and reperfusion has been shown to play a prominent role in the development of myocardial stunning and infarction. To determine if a simple inhibitor of neutrophil adhesion could reduce myocardial infarct size, we administered NPC 15669 (a new antiinflammatory agent that inhibits neutrophil adhesion) to 12 pigs (6 controls, 6 NPC-treated) in a porcine model of ischemia and reperfusion injury. Each animal received a continuous infusion of either NPC (10 mg/kg intravenous bolus followed by 6 mg.kg-1 x h-1 intravenous infusion) or an equal volume of normal saline solution during 1 hour of left anterior descending artery occlusion and 2 hours of reperfusion. There were no significant differences in the pre-ischemia, mid-ischemia, or postischemia rate-pressure product between control and experimental groups. The regions at risk were similar in both groups. However, the mean myocardial infarct size was reduced by 51% with administration of NPC 15669 (30.7% +/- 6.8%) compared with controls (62.3% +/- 5.4%; p < 0.01). These data indicate that NPC 15669, an inhibitor of neutrophil adhesion, substantially reduces myocardial infarct size after transient left anterior descending artery occlusion and that adhesion of the white cell to vascular endothelium may be an important element of the pathogenesis of myocardial infarction.

Animals↗

PubMed1993

EEG and prognosis of neurologic recovery of dogs under profound hypothermic circulatory arrest.

Deep hypothermia (18-20 degrees C) (DH) during prolonged circulatory arrest and cardiopulmonary bypass is used to repair complex intracardiac lesions and vascular neurosurgical lesions. DH diminishes the risk of ischemic damage and multiorgan failure after circulatory arrest. Profound hypothermia (PH) to 6-7 degrees C has recently been reported to improve the neurological outcome of dogs after 2 h of circulatory arrest. There are no reports of the possible utility of EEG activity to predict the neurological outcome. As a part of a controlled study of cardiopulmonary bypass and 2 h of circulatory arrest we compared EEG recovery to the neurological outcome in 2 groups of dogs: 4 under DH and 4 under PH. All of the dogs under PH had a good outcome: mean neurodeficit score was 6.25/500 in PH and 139.25/500 in DH dogs (P < 0.03); mean histopathological score was 19.25/100 for DH and 47.75/100 in PH dogs (P < 0.03). EEG activity 2 h after reperfusion and starting of rewarming correlated with eventual neurological outcome. EEG variables associated with good outcome were: main final frequency and degree of rhythmicity of the activity. We conclude that PH exerted a protective effect for animals undergoing 2 h of circulatory arrest. EEG was a useful tool for predicting neurological outcome under the studied conditions.

Animals↗

PubMed1993

Centrifugal ventricular assist device for support of the failing heart after cardiac surgery.

OBJECTIVE: To determine the morbidity and mortality associated with use of centrifugal ventricular assist devices for postcardiotomy cardiogenic shock and to determine factors that might influence outcome and thus, aid in patient selection. DESIGN: A retrospective study. SETTING: Surgical intensive care unit in a university hospital. PATIENTS: During a 6-yr period, a total of 7,385 adult patients underwent cardiac operations requiring cardiopulmonary bypass. Myocardial protection consisted of single-dose cold crystalloid cardioplegia and continuous topical hypothermia by saline lavage. A total of 72 (1%) patients developed postcardiotomy cardiogenic shock. Of 72 patients, 28 met the institutional criteria and were placed on centrifugal ventricular assist devices. INTERVENTIONS: Twenty-eight adult patients with postcardiotomy cardiogenic shock were supported with centrifugal ventricular assist devices. MEASUREMENTS AND MAIN RESULTS: A total of 15 patients received left ventricular assist devices, five received right ventricular assist devices, and eight received both right and left ventricular assist devices. Mean age of ventricular assistance patients was 50.8 +/- 12.9 yrs (range 22 to 72), and mean duration of ventricular assistance was 2.8 +/- 2.5 days (range 4 hrs to 10 days; median 2 days). Twenty-five complications occurred in 16 patients and included bleeding (13), tamponade (2), systemic embolism (6), seizures (2), and sepsis (2). Nine patients required reexploration for bleeding or tamponade. Nine (32%) of 28 patients were discharged from the hospital. Ventricular assistance for cardiac failure after transplantation was associated with improved survival (p < .10), while age > 50 yrs and postoperative tamponade each showed trends toward association with mortality (p = .10). Survival was not predicted by gender, weight, time on cardiopulmonary bypass, aortic cross-clamp time, urgency of operation, or preoperative congestive heart failure. At 27 +/- 20 months follow-up, all survivors were alive and New York Heart Association functional class I or II. CONCLUSIONS: These results document a low incidence of ventricular assist device use in a surgical practice that employs a relatively simple method of myocardial protection. When postcardiotomy ventricular assistance was necessary, a centrifugal pump was used and successful outcome and satisfactory long-term results were possible in nearly one third of patients. Ventricular assistance for cardiac failure after transplantation was associated with improved survival. Older age is a relative contraindication to mechanical ventricular assistance.

Adult↗

PubMed1993

Protection of the internal mammary artery pedicle with polytetrafluoroethylene membrane.

With increasing frequency, reoperative coronary artery bypass surgery is being performed in the setting of a patent internal mammary artery (IMA) graft. Injury to the IMA graft at reoperation can result in ischemic myocardial injury and cardiac arrest. This descriptive laboratory study examined use of a polytetrafluoroethylene (PTFE) membrane wrap to protect the IMA pedicle during sternal reentry. Six pigs (25-30 kg) underwent median sternotomy and takedown of left and right IMAs. Grafts were implanted in the epicardium by a modified Vineberg procedure. In each animal, one IMA was wrapped circumferentially with PTFE, while the contralateral bare IMA served as the control. Redo sternotomy was performed 3 months later. Severe adhesions between chest wall, myocardium, and bare IMA grafts were encountered in six of six animals. PTFE-wrapped IMAs were easily identified by appearance and by palpation. There was no adherence between PTFE membranes and surrounding tissue, nor was there evidence of cellular infiltration, disruption, or contraction of the membrane. Most notably, PTFE membranes could not be cut or injured with the electrocautery, since they are electrical nonconductors. This study demonstrates that PTFE membrane: (1) is relatively inert and incites minimal surrounding tissue reaction; and (2) is impenetrable to electrocautery injury. Further studies are necessary to determine the impact of PTFE membrane on IMA graft patency and wound infection. PTFE membrane may prove clinically useful in protecting patent IMA pedicles during reoperative cardiac surgery.

Animals↗

PubMed1993

Inhibition of neutrophil adherence improves postischemic ventricular performance of the neonatal heart.

BACKGROUND: Reduction of the leukocyte population during postischemic coronary reperfusion results in decreased neutrophil-mediated tissue injury. However, the importance of leukocyte adhesion to coronary endothelium for postischemic ventricular dysfunction after global hypothermic myocardial ischemia is unknown. Neutrophil integrins (CD11b/CD18) upregulate in response to cardiopulmonary bypass and ischemic stress, and their role in generating postoperative ventricular dysfunction was examined in this study. METHODS AND RESULTS: An in vivo, in situ model of neonatal cardiac surgery was established in which neutrophil adherence was manipulated by administering NPC 15669 (an inhibitor of neutrophil CD11b/CD18 surface receptor upregulation). Seventeen 3- to 5-day-old piglets (8 controls and 9 NPC 15669-treated animals) were instrumented with a coronary sinus catheter, sonomicrometry crystals across the short axis of the left ventricle (LV), and a micromanometer positioned in the LV. Hearts were subjected to 90 minutes of hypothermic ischemia after a single dose of cold crystalloid cardioplegia. Myocardial granulocyte accumulation during ischemia and reperfusion was reduced in NPC animals compared with controls (myeloperoxidase activity, 43.4 +/- 2.6 and 75.8 +/- 6.3 mumol/10 mg tissue, respectively; P < or = .005). This was associated with a reduction in coronary vascular resistance in NPC animals compared with controls (P < or = .02) and decreased release of myocardial creatine phosphokinase throughout reperfusion (P < or = .05). NPC animals demonstrated an improved preservation of the end-systolic pressure-volume relation after discontinuation of cardiopulmonary bypass (71 +/- 6% and 96 +/- 6% at 60 minutes, respectively; P < or = .05). There was no difference in ventricular compliance between groups. CONCLUSIONS: These data demonstrate that inhibition of neutrophil CD11b/CD18 surface adherence receptor upregulation reduces granulocyte accumulation in myocardium after hypothermic global ischemia, reduces myocyte damage, and improves ventricular systolic function.

Animals↗

PubMed1993

Temporary leukocyte depletion reduces ventricular dysfunction during prolonged postischemic reperfusion.

Leukocyte depletion improves early postischemic ventricular performance in neonatal models of global myocardial ischemia. However, the rate of leukocyte reaccumulation after cardiopulmonary bypass and its subsequent impact on myocardial function is not known. This laboratory study examined the effect of leukocyte depletion on myocardial performance during the initial 6-hour period after bypass in an in situ, in vivo porcine model of neonatal cardiac surgery. Fifteen 3- to 5-day-old piglets (eight control and seven leukocyte depleted animals) were instrumented by placement of left ventricular short-axis sonomicrometry crystals and an intraventricular micromanometer catheter. Mechanical leukocyte depletion was achieved with Pall RC100 filters (Pall Biomedical, Inc., Fajardo, Puerto Rico) in the cardiopulmonary bypass circuit. Neonatal hearts were subjected to 90 minutes of hypothermic ischemia after a single dose of cold crystalloid cardioplegia. Two control animals died after the operation and were excluded from data analysis. Leukocyte filtration reduced the granulocyte count during initial myocardial reperfusion to 0.8% of control values. However, circulating granulocyte counts increased in leukocyte depleted animals throughout the postoperative period, reaching 68% of control values by 6 hours. Despite this rapid return of circulating granulocytes, animals subjected to leukocyte depletion had significantly better preservation of left ventricular performance (measured by preload recruitable stroke work, p < or = 0.02), left ventricular systolic function (measured by end-systolic pressure-volume relationship, p < or = 0.05), and ventricular compliance (p < or = 0.04) during the experiment. These changes in ventricular function were associated with a significant increase in left ventricular water content (p < or = 0.02) and tissue myeloperoxidase activity (p < or = 0.005) in control animals compared with leukocyte depleted animals. This study demonstrates that leukocyte depletion during initial reperfusion results in sustained improvement in postischemic left ventricular function despite the rapid return of granulocytes to the circulation.

Animals↗

PubMed1993

The monosialoganglioside, GM1, reduces neurologic injury associated with hypothermic circulatory arrest.

BACKGROUND: Neurologic injury associated with prolonged hypothermic circulatory arrest (HCA) may be mediated by calcium-dependent glutamate excitotoxicity (GE). The monosialoganglioside GM1 has been shown in vitro to limit GE in conditions of metabolic stress. To test the hypothesis that gangliosides can prevent HCA-induced brain injury, GM1 was used in a canine model of HCA. METHODS: Twelve male dogs were placed on closed-chest cardiopulmonary bypass, subjected to 2 hours of HCA at 18 degrees C, and rewarmed to 36 degrees to 37 degrees C on closed-chest cardiopulmonary bypass. All were mechanically ventilated and monitored for 20 hours before extubation and survived for 3 days. Group 1 dogs (n = 6) were pretreated with GM1, 30 mg/kg/24hr for 3 days before HCA, and received continuous infusion of GM1 during the procedure and 30 mg/kg/24hr for 3 days after HCA. Group 2 dogs (n = 6) received vehicle only. With a species-specific behavior scale that yielded a neurodeficit score ranging from 0% (normal) to 100% (brain dead), all animals were neurologically assessed every 12 hours. After death at 72 hours, brains were examined by glutamate receptor autoradiography and by histologic examination for patterns of selective neuronal necrosis and were scored blindly from 0 (normal) to 100 (severe injury). RESULTS: Group 1 dogs had better neurologic function compared with group 2 (neurodeficit score, 4.2% +/- 3% vs 38.4% +/- 8%; p < 0.001) and had less neuronal injury (11.3 +/- 3 vs 48.3 +/- 9, p < 0.001). Densitometric receptor autoradiography revealed preservation of neuronal glutamate receptor expression in group 1 only. CONCLUSIONS: These results provide evidence of a role for GE in the development of HCA-induced brain injury and suggest that monosialogangliosides may have a neuroprotective capacity in prolonged periods of HCA.

Animals↗

PubMed1993

Composite aortic valve replacement and graft replacement of the ascending aorta plus coronary ostial reimplantation: how I do it.

Aortic root replacement in the patient with Marfan syndrome is indicated in the presence of aortic root dilatation more than 6 cm, ascending aortic dissection, or 3 to 4+ aortic valve insufficiency. The objective of operation is to prevent catastrophic aortic rupture or dissection and to treat or prevent aortic insufficiency with consequent left ventricular dysfunction. In over 170 patients undergoing aortic root replacement, operative mortality has been 1%. At mean follow-up of 5 years, the survival rate was 75%. The most frequent serious late postoperative complication has been graft endocarditis (4%). The technique described above carries a low operative risk and late complication rate. We believe it is an important surgical arm in the treatment of cardiovascular complications of the Marfan syndrome.

Aortic Dissection↗

PubMed1992

Surgical treatment of postinfarction ventricular septal defect with aortic stenosis.

A 69-year-old man with an acute postinfarction ventricular septal defect was also found to have aortic stenosis. Successful management required closure of the postinfarction ventricular septal defect and replacement of the stenotic aortic valve. The contribution of aortic stenosis to the cause of the infarction and the postinfarction ventricular septal defect, as well as the implications for surgical management, are discussed.

Aged↗

PubMed1992

Hypothermic circulatory arrest as a surgical adjunct: a 5-year experience with 60 adult patients.

As a surgical adjunct, the technique of hypothermic circulatory arrest (HCA) is well established in pediatric cardiac surgery but is used less frequently in adults. This study was undertaken to review the application, utility, and safety of HCA in adult surgery at a single institution. Between January 1985 and October 1990, 60 adult patients (greater than 18 years old) underwent surgical procedures that included HCA. There were 30 men and 30 women; mean patient age was 56.4 years (range, 20 to 81 years). Operative procedures were thoracic aortic aneurysm repair (35 patients, 58%), resection of intraabdominal malignancy (15 patients, 25%), coronary artery bypass (4 patients, 7%), and other miscellaneous procedures (6 patients, 10%). Eighty-two percent of the procedures were elective, whereas 18% were emergencies. Mean circulatory arrest time was 28.5 minutes (range, 2 to 64 minutes). Operative mortality was 15%; by multivariate analysis, risk factors for death included prolonged cardiopulmonary bypass time (p less than 0.05), higher post-HCA rectal temperature (p less than 0.05), and intraoperative hypotension (p less than 0.001). Patient age, sex, emergency status, duration of HCA, and perfusion variables on cardiopulmonary bypass did not predict operative mortality. The incidence of perioperative neurologic injury was 15%. The only risk factor for neurologic injury was intraoperative hypotension (p less than 0.05). One- and 3-year actuarial survival for patients undergoing operation on the heart or great vessels was 75.9% and 70%, respectively, whereas patients with intraabdominal malignancy had 75% and 23.4% 1- and 3-year survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗