Use of cryopreserved vein allogeneic homografts in liver transplantation.
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Cryopreservation↗
Biomedical subjects
R B Karp
Publications and source records attributed to R B Karp.
Thromboelastogram fails to predict postoperative hemorrhage in cardiac patients.
To determine the clinical usefulness of the thromboelastogram in the prediction of postoperative hemorrhage in cardiac patients, we related the results of routine coagulation tests (RCTs) and thromboelastography with the amount of chest tube drainage postoperatively in 101 patients requiring cardiopulmonary bypass. Our data indicated that there was no correlation between RCT results and thromboelastographic variables. No single variable of RCTs and thromboelastography correlated well with the amount of chest tube drainage postoperatively. Before the onset of cardiopulmonary bypass, the most frequent abnormalities detected by thromboelastograms were fibrinolysis and hypocoagulability resulting from factor deficiency. Hypercoagulability detected by thromboelastograms occurred in 13% of patients after cardiopulmonary bypass and usually was not detected by RCTs. The incidence of false-negative thromboelastograms and RCT results in patients who had excessive hemorrhage of unknown cause was 46% and 52%, respectively. The incidence of fibrinolysis as detected by thromboelastograms was similar before and after bypass, but only 2 of the 18 patients with fibrinolysis had excessive hemorrhage postoperatively. Our results indicate that neither RCTs nor thromboelastography predicts the likelihood of excessive hemorrhage in patients after cardiopulmonary bypass. The thromboelastographic results should be interpreted cautiously because of the high rate of unreliable results.
Blood Coagulation Tests↗
Monitoring of heparin-induced anticoagulation with kaolin-activated clotting time in cardiac surgical patients treated with aprotinin.
High-dose aprotinin appears to enhance the anticoagulant effects of heparin, as documented by increases in the activated clotting times (ACTs) during cardiopulmonary bypass; hence, some authorities have advocated reducing the dose of heparin in patients treated with aprotinin. An in vitro study by our group suggested that the increase of the ACT in the presence of aprotinin and heparin may be due to the use of celite as surface activator. We compared celite and kaolin as surface activators for the measurement of the ACT in cardiac surgical patients treated with aprotinin and in patients given no aprotinin. This double-blind, randomized, placebo-controlled study included 30 patients, of whom 14 received aprotinin and 16 received a placebo. Before, during, and after cardiopulmonary bypass, the ACT was measured with two Hemochron 400 systems with 12 mg of either celite (C-ACT) or kaolin (K-ACT) used as surface activator and with one Hepcon HMS system (HR-ACT), which uses kaolin as activator. The latter also was used for measurement of the blood heparin concentration. The ACTs of blood without heparin did not differ between aprotinin and control patients. During anticoagulation with heparin and cardiopulmonary bypass, the average C-ACTs were 784 +/- 301 s (aprotinin) and 496 +/- 120 s (control) (P < .001); the K-ACTs were 502 +/- 131 s (aprotinin) and 458 +/- 101 s (control) (P > .05); the HR-ACTs were 406 +/- 87 s (aprotinin) and 423 +/- 82 s (control) (P > .05), which was consistently less than C-ACT and K-ACT.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Sex-associated differences in left ventricular function in aortic stenosis of the elderly.
BACKGROUND: In aortic stenosis, the response of the left ventricle to pressure overload varies from compensated hypertrophy to overt heart failure. The determinants of left ventricular adaptation are poorly understood. METHODS AND RESULTS: Left ventricular function was compared to assess the role of sex in 34 women and 29 men 60 years or older with both hemodynamic and echocardiographic data characteristic of severe aortic stenosis and no important coronary artery disease. Despite a similar degree of left ventricular outflow obstruction in women versus men (aortic valve area 0.54 +/- 0.20 versus 0.59 +/- 0.19 cm2, NS), the left ventricle of women had a greater fractional shortening (37 +/- 12 versus 25 +/- 12%, p = 0.001), achieved a smaller end-systolic chamber size (1.82 +/- 0.64 versus 2.17 +/- 0.65 cm/m2, p = 0.04), and generated more pressure (210 +/- 35 versus 182 +/- 29 mm Hg, p = 0.001) with a greater maximum positive dP/dt (2.153 +/- 794 versus 1,595 +/- 384 mm Hg/sec, p = 0.02). The men had a lower cardiac index (2.12 +/- 0.59 versus 2.49 +/- 0.63 l/min/m2, p = 0.02), higher mean pulmonary artery pressure (35 +/- 13 versus 27 +/- 10 mm Hg, p = 0.01), and shorter ejection period (340 +/- 40 versus 370 +/- 40 msec, p = 0.02). Women and men were equally symptomatic. Supernormal left ventricular ejection performance was present in 41% of the women and only 14% of the men (p = 0.002). This subgroup of women had a small, thick-walled chamber (end-diastolic radius to thickness ratio, 1.58 +/- 0.52 versus 2.45 +/- 0.51 in control women, p = 0.01) with low end-systolic wall stress. Subnormal ejection performance was present in 64% of the men and only 18% of the women (p = 0.002). This subgroup of men had an increased chamber size and high end-systolic wall stress compared with control men. Greater left ventricular mass was present in men compared with women (211 +/- 55 versus 179 +/- 55 g/m2, p = 0.03). CONCLUSIONS: Sex is a factor in left ventricular adaptation to valvular aortic stenosis in adults 60 years or older.
Aged↗
In vitro effects of aprotinin on activated clotting time measured with different activators.
The effects in vitro of aprotinin on the activated clotting time measured with both celite- and kaolin-activated tubes were investigated in 21 consecutive patients requiring cardiopulmonary bypass. Four whole-blood samples (2 ml per sample) from each patient were tested simultaneously with Hemochron automated timing systems (International Technidyne Corp., Edison, N.J.) before, during, and after cardiopulmonary bypass. One tenth milliliter of either aprotinin (at a final concentration of 80, 120, or 180 KIU/ml) or saline solution was mixed in vitro with blood samples before determination of the activated clotting time. Aprotinin had no inhibitory effect on the activated clotting times of unheparinized blood. After heparin administration, aprotinin in the above concentrations prolonged the activated clotting times measured with celite-activated tubes by 47% to 71%, as compared with the measurements of the activated clotting time without the addition of aprotinin. The activated clotting times in kaolin-activated tubes were not increased, however, by the in vitro addition of aprotinin. Our in vitro results indicate that aprotinin in concentrations from 80 to 180 KIU/ml does not significantly enhance the inhibitory effects of heparin on the intrinsic coagulation system as evaluated by measurement of the activated clotting times in kaolin-activated tubes. The anticoagulation effect of heparin in patients receiving aprotinin infusion should be monitored with kaolin-activated instead of celite-activated tubes because the celite makes the measured activated clotting time unreliable in patients receiving aprotinin therapy. These in vitro results require confirmation in vivo in patients receiving aprotinin therapy.
Aged↗
Evaluation of cryopreserved allograft venous conduits in dogs.
We investigated the effects of cryopreservation, immunosuppression, and antibiotic treatment on the patency and histologic appearance of venous conduits in the arterial circulation. Twenty-eight dogs received arterial replacements with autograft vein, fresh allograft, and two types of cryopreserved allograft vein implanted into both carotid and both femoral arteries. All animals were given aspirin, and half were given cyclosporine. After 3 months the vein grafts were harvested. Patency and light, transmission, and scanning electron microscopic criteria were scored to evaluate quality of preservation of the endothelium, the appearance of rejection, and the effects of cryopreservation with and without antibiotic pretreatment. The results show that patency is not statistically different based on graft type or treatment modality. The histologic appearance among the various vein types was remarkably similar at 3 months, with the exception of a cellular infiltrate present most prominently in the fresh allografts and least in the fresh autografts. Cyclosporine, even at a low dose, decreased the incidence of cellular infiltration. Preservation of endothelium was generally good in the cryopreserved allografts both with and without antibiotic pretreatment. In general, the effects of cryopreservation, cyclosporine, and antibiotics ameliorated the effects of venous allografting into an arterial position.
Animals↗
Assessment of retrograde cardioplegia distribution using contrast echocardiography.
Retrograde cardioplegia has gained popularity in coronary and noncoronary cardiac operations. We have used contrast echocardiography in the open-chest canine model to compare the distribution of cardioplegia delivered antegrade in the aortic root versus retrograde through the coronary sinus, and to determine the effect of coronary occlusion on that delivery. With no coronary occlusion, antegrade cardioplegia was distributed to the entire left ventricle and septum whereas retrograde cardioplegia was distributed to the left ventricular free wall but had inconsistent delivery to the septum. Acute occlusion of the left circumflex coronary artery resulted in 57.06% +/- 9.52% of the left ventricle not being perfused by antegrade cardioplegia and occlusion of both the left circumflex and anterior descending coronary arteries caused a 65.46% +/- 18.5% reduction in perfusion by antegrade cardioplegia. Acute coronary occlusion had no effect on retrograde cardioplegia distribution. We conclude that retrograde cardioplegia is less homogeneous than antegrade cardioplegia in the intact coronary circulation but that retrograde cardioplegia preserves cardioplegia distal to acutely occluded coronary arteries. Furthermore, contrast echocardiography is a useful method of assessing myocardial perfusion and may have useful clinical applications.
Albumins↗
Assessment of myocardial perfusion during CABG surgery with two-dimensional transesophageal contrast echocardiography.
No reliable, quantifiable index of tissue perfusion is currently available to assess the efforts of coronary artery bypass graft (CABG) surgery. We used two-dimensional transesophageal contrast echocardiography with sonicated Renografin-76 microbubbles to determine the distribution of myocardial blood flow during coronary artery bypass graft surgery in 15 patients. Sonicated Renografin-76 contrast agent was injected into the aortic root of all patients after institution of cardiopulmonary bypass and application of the aortic occlusive clamp. Eight patients had contrast agent injected directly into the free proximal end of the vein-CABG anastomosis. All patients again received aortic root injections during reperfusion after anastomosis of the proximal aortovein and distal coronary artery. Echocardiographic images of the left ventricle short axis at the level of the papillary muscles were obtained in real time and analyzed retrospectively from videotape. Injection of contrast provided information about the magnitude and geometric distribution of coronary artery-vein bypass run-off and enabled identification of poorly perfused myocardial regions. When predicted myocardial perfusion patterns, based on preoperative evaluation of epicardial vessel distribution derived from coronary angiography, were compared to actual perfusion patterns assessed with intraoperative echocardiography, contrast regional myocardial perfusion patterns were predicted 84% of the time (71-97%, 95% confidence limit). Regional myocardial perfusion deficits detected after coronary bypass grafting were associated with regional wall motion abnormalities detected after separation from cardiopulmonary bypass. Our technique makes possible on-line visualization of changes in regional blood flow in the heart before, during, and after CABG.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Prediction of aortic annulus diameter by two-dimensional echocardiography. Application in the preoperative selection and preparation of homograft aortic valves.
The preoperative selection and preparation of an appropriately sized homograft aortic valve would allow delay of surgery if a suitable valve were unavailable, thus pre-emptying inventory limitations, and a decrease of ischemic time in cases of isolated aortic valve replacement. An accurate preoperative measurement of the aortic annulus diameter is the prerequisite for such selection. The aortic annulus diameter was measured retrospectively in a blinded fashion from the two-dimensional echocardiograms of 62 patients who underwent aortic valve replacement with mechanical or bioprosthetic valves. Measurements were obtained with electronic calipers by two observers. Confidence in the accuracy of the measurement obtained was ranked on a scale from 1 to 5. The mean difference between echocardiographic measurements and prosthetic valve sizes was 0.39 +/- 0.46 mm (mean +/- 2SD) for observer 1 and -0.26 +/- 1.44 mm for observer 2. Ninety-eight percent of observer 1 measurements and 80% of observer 2 measurements were within 1.5 mm of the prosthetic valve size (p less than 0.01 for differences between observers). Confidence scores were higher for observer 1 and for both observers were related to accuracy. The aortic annulus diameter of eight patients scheduled for homograft aortic valve replacement was measured prospectively with the same technique. There was an excellent agreement between the two-dimensional echocardiographic measurements and the surgical measurements. In the last 5 consecutive patients, the echocardiographic measurement was used for the preoperative selection and preparation of the appropriate valve. In conclusion, measurement of the aortic annulus diameter by two-dimensional echocardiography is feasible and clinically useful for the preoperative selection and preparation of homograft aortic valves.(ABSTRACT TRUNCATED AT 250 WORDS)
Aortic Valve↗
Guidelines for the early management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Subcommittee to Develop Guidelines for the Early Management of Patients with Acute Myocardial Infarction)
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American Heart Association↗
ACC/AHA guidelines for the early management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (subcommittee to develop guidelines for the early management of patients with acute myocardial infarction).
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Angioplasty, Balloon, Coronary↗
Contrast echocardiography: a method to visualize changes in regional myocardial perfusion in the dog model for CABG surgery.
The ability of contrast echocardiography to assess regional myocardial perfusion during cardiopulmonary bypass in a dog model for coronary artery bypass surgery was evaluated. Sonicated Renograffin-76 microbubbles (meglumin diatrigoate and sodium diatrigoate) were injected into an aortic root proximal to an aortic occlusion clamp root while dogs were on cardiopulmonary bypass, with the heart arrested in diastole. Echocardiographic contrast-enhanced regions of myocardial perfusion were easily visualized. Differences in contrast-enhanced myocardial regions depended on coronary artery occlusion or patency. The contrast-enhanced images of myocardial perfusion showed that, for a given myocardial segment of the supplying vessel, the presence or absence of contrast effect reliably predicted vessel occlusion or patency (P less than .01). In the future contrast echocardiography may allow the direct assessment of regional myocardial perfusion in the operating room.
Animals↗
Ultrasonic debridement of the aortic valve with six-month echocardiographic follow-up.
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Aged↗
Congenital left atrial aneurysm in an infant.
Congenital left atrial aneurysm, without associated cardiac abnormalities, is a rare defect. We report the case of a large left atrial aneurysm filling almost the entire left hemothorax. This is the first report of this anomaly occurring in an infant less than 1 year of age.
Female↗
Aortic root replacement for complicated bacterial endocarditis in an infant.
We report the case of a 10-week-old girl with streptococcal aortic valve endocarditis that was resistant to medical management and complicated by aortic insufficiency, congestive heart failure, annular abscess, and a large periaortic pseudoaneurysm. She underwent successful aortic valve and root replacement (with coronary artery reimplantation) utilizing an aortic valve homograft (allograft). The patient recovered completely and was discharged 3 weeks postoperatively. To our knowledge, this is the youngest patient to receive an aortic homograft for bacterial endocarditis and annular abscess.
Aorta↗
Coronary artery bypass grafting in the presence of valvular disease.
Compared with isolated coronary artery bypass grafting (CABG), the combination of valve replacement or repair with coronary revascularization generally increases operative risk. However, complete revascularization is superior to no revascularization in patients with valvular and coronary artery disease (CAD). Patients who undergo aortic valve replacement and CABG have two unrelated disease processes; these patients only infrequently have ischemic cardiomyopathy, and the operative mortality is slightly increased to 4-7% for the combined procedure versus isolated aortic valve replacement. Patients who are operated on for mitral valve disease and CAD fall into two groups: 1) where CAD and mitral valve disease are not etiologically related, and 2) where mitral valve dysfunction is the result of ischemic changes. In the latter group, operative mortality significantly exceeds that for isolated mitral valve surgery, and surgical priority increases that difference (operative mortality 7-20%). Thus, the operative risk for a mitral valve procedure plus CABG exceeds that for isolated coronary revascularization or isolated valve replacement. In the combined procedure, risk increases if valve dysfunction is caused by CAD, if severe left ventricular function is present, if the patient has been assigned to Class IV, or if emergency operation is required.
Aortic Valve↗
Preservation of myocardial high energy phosphates during cardioplegic arrest with nifedipine.
Nifedipine used both as an additive to cardioplegia solution (CPS) and as pretreatment prior to arrest was studied in a rat model to determine its effect upon ischemic ventricular electromechanical work during arrest and upon high energy phosphate levels. Fifty-one normothermic rats were studied in vivo with infusion of hypothermic (4 degrees C) CPS into the cross-clamped aortic root according to one of the following eight protocols: Group 1, baseline beating hearts; Group 2, CPS containing 15 mEq potassium chloride/liter (KCl/liter); Group 3, CPS containing 30 mEq KCl/liter; Group 4, CPS containing 15 mEq KCl/liter combined with stimulation of the vagus nerve; Groups 5 and 6, CPS with 15 mEq KCl/liter and containing 250 or 500 micrograms of nifedipine per liter; Groups 7 and 8, pretreatment with 100 or 200 micrograms nifedipine/kg given as an intravenous bolus 15 min prior to infusion of CPS with 15 mEq KCl/liter. Time to arrest, number of ischemic ventricular contractions after aortic cross clamping, and ATP and creatine phosphate (CP) levels were recorded. All nifedipine groups arrested more quickly and with fewer ventricular contractions and had ATP and CP levels higher than those of Group 2 (P less than 0.05). There were no differences between the nifedipine groups and Group 3 except that Group 8 (200 micrograms/kg pretreatment) resulted in higher levels of CP than Groups 3, 5, and 6 (P less than 0.05 for all groups). When all groups were combined, time to arrest correlated negatively with ATP (r = -0.863, P less than 0.01) and CP (r = -0.824, P less than 0.01) levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine Triphosphate↗
Analysis of morbid events and risk factors for death after cardiac transplantation.
Risk factors for death after cardiac transplantation performed at the University of Alabama at Birmingham from January 1981 to July 1985 included (by multivariate analysis) higher calculated preoperative pulmonary vascular resistance (early and constant phases), morphology of cardiomyopathy (versus ischemic heart disease) (constant phase only) and black race (constant phase). Overall actuarial survival was 71% at 1 year and 48% at 3 years (including azathioprine and cyclosporine eras). The hazard function for death was highest immediately after operation and declined rapidly thereafter, merging with a constant phase of risk at about 3 months. The most favorable group for long-term survival was the group of white patients with ischemic heart disease and low pulmonary vascular resistance. When such patients had a pulmonary vascular resistance less than 3 units.m2, the 3 year survival rate exceeded 85%. The most common causes of death were acute rejection (24%) and infection (17%). The risk of infection remained highest during the first several months after any period of augmented immunosuppression.
Acute Disease↗