Antiplatelet and anticoagulant therapy after coronary bypass.
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Anticoagulants↗
Biomedical subjects
H B Barner
Publications and source records attributed to H B Barner.
Embolization of extensive peripheral angiodysplasias. The alternative to radical surgery.
We describe two patients with extensive pelvic and lower limb angiodysplasias, in whom hemodynamic complications subsequently developed. These have been treated by selective angiography and multiple percutaneous transcatheter embolizations with satisfactory results (1 1/2 to four years of follow-up). One patient had had three previous operations with no improvement; amputation was the only surgical alternative. In the other patient, hip disarticulation and hemipelvectomy was seriously considered because of cardiac failure not responding to medical therapy. We review the literature and use our cases to illustrate points of technique and reemphasize the essential role of therapeutic embolization in the management of extensive angiodysplasia.
Adolescent↗
Clinical experience with cold blood as the vehicle for hypothermic potassium cardioplegia.
Intermittent cold ischemic arrest was compared with hypothermic potassium cardioplegia using cold blood as the vehicle in two consecutive series of patients having isolated coronary bypass grafting. Between January 1, 1977, and June 30, 1977, 196 patients were operated on using cold ischemic arrest. The incidence of perioperative infarction was 14.3%, and mean total myocardial ischemia time was 42 +/- 1.2 minutes. From July 1, 1977, to June 30, 1978, there were 428 operations done using cold blood with potassium. The incidence of perioperative infarction was 5.6% (p less than 0.005), and the mean total myocardial ischemic time was 80 +/- 2.1 minutes. In the five years prior to this study, the incidence of perioperative infarction was constant at 13% while operative mortality was declining from 5 to 1% and the need for postoperative myocardial support was declining also. Use of cold blood potassium cardioplegia compared with cold ischemic arrest for myocardial protection during coronary artery operations has significantly reduced the incidence of perioperative infarction while doubling cross-clamp time.
Aspartate Aminotransferases↗
The effect of coronary artery bypass on longevity. A surgeon's viewpoint.
Enthusiasm for new therapeutic modalities frequently results in a ground swell of overuse, which recedes to leave a trough of negativism before a definitive level is established. In the case of CABG, the ground swell has become a 10-year flood tide, without an ebb, although ripples have marred the surface. It is generally agreed that suitable control populations are needed to determine the role of a therapy and that the best controls would arise from randomized prospective trials. At present, the best randomized trial is the VA study which has shown that operation does not enhance longevity for single vessel disease, but clearly does for left main coronary disease. In those individuals with two- and three-vessel disease, the VA study has not shown that surgical therapy is better than medical treatment. However, three other studies containing patients selected by the VA criteria indicate that operation provides significantly greater longevity for patients in these two categories. Acceptance of this position requires acknowlegement of the validity of the VA study and the comparison of extramural concurrent surgical series.
Coronary Artery Bypass↗
Does myocardial protection work?
These data would suggest that hypothermia combined with potassium cardioplegia enhances protection of the ischemic myocardium over other available techniques. The ideal conduct of this myocardial protection is not yet apparent but certain aspects are worthy of emphasis. (1) With the onset of ischemia cardioplegia should be immediately induced to abolish contractile activity and conserve energy. An advantage of blood cardioplegia is that there is no ischemia or it is trivial priorto cardioplegia. (2) The greater the degree of myocardial cooling the better. Although a myocardial temperature of 20 degrees C can commonly be achieved with perfusion hypothermia and topical hypothermia, it is possible to reduce myocardial temperature to 10 degrees C or lower with these same modalities. Because perfusion hypothermia provides fairly uniform rapid myocardial cooling, this should be maximally utilized by cooling of the systemic perfusate to 20 degrees C and cooling the cardioplegic infusate to 4-10 degrees C. Cardiac hypothermia should be maintained with crushed ice made from electrolyte solution or irrigation of the pericardial sac with cold electrolyte solution. The greater the degree of systemic hypothermia the less tendency for the myocardium to warm. (3) The ideal concentration of potassium is unknown at this time with a range of 15-40 mEq/l having been utilized without apparent potassium injury. (4) The ideal composition of the vehicle may never be defined and may not be of great importance. Whole blood would appear to offer physiological and pragmatic advantages over asanguinous vehicles. (5) The safe duration of ischemia has been moderately well defined. 1 h is well tolerated in the dog using profound cardiac hypothermia, whereas 30-45 min with lesser degrees of hypothermia is acceptable. When the interval of ischemia is to be 2 or 3 h reinfusion of potassium every 20-30 min has proven safe both experimentally and clinically.
Chelating Agents↗
The rationale for operative therapy of symptomatic single-vessel coronary artery disease.
During an 8 year interval, 184 patients with symptomatic single-vessel disease underwent coronary artery bypass grafting (CABG). There were no operative deaths and only one late cardiac death (5 year cumulative survival 97.9%). At 48 months mean follow-up, 91% are angina free or improved. The low incidence of perioperative and late myocardial infarction (MI) and the preservation of ventricular function seen on follow-up catheterization suggest that coronary bypass operations yield significant benefits in severely symptomatic patients with single-vessel disease. Evidence is presented which supports the idea that single-vessel coronary artery disease may be a unique manifestation of coronary atherosclerosis and not one stage in a continuum.
Angiocardiography↗
Bypass grafts to the left anterior descending coronary artery: saphenous vein versus internal mammary artery.
During the interval 1972 to 1977, of 1,522 patients undergoing isolated coronary artery bypass grafting (CABG), 1,459 received grafts to the left anterior descending coronary artery (LAD). Internal mammary artery (IMA) was used in 765 patients and reversed saphenous vein graft (SVG) in 694 patients. Choice of bypass graft was nonrandom. Clinical follow-up is available in 98% of patients. Angiography has been obtained in 69% of eligible patients at 1 month, 65% at 1 year, 62% at 3 years, and 63% at 5 years. There was no difference in operative mortality rates (IMA 1.4%, SVG 1.9%) or 5 year actuarial survival rates (IMA 87.6%, SVG 88.7%). Graft flows were consistently higher at operation with the SVG, but patency rates at each interval were significantly higher with the IMA. Perioperative and late myocardial infarction occurred significantly less often in IMA patients. Superiority in IMA graft patency became apparent after an initial "learning curve" of 2 years of experience. Maintenance and/or restoration of normal left ventricular function was more common in IMA patients operated upon after the initial 2 year experience. IMA grafts are recommended for LAD bypass when the LAD is 2.0 mm in diameter or less. Early results with sequential SVG to the LAD suggest that this may be a realistic alternative to the IMA and may approach the 1 year IMA graft patency rate of 92.6%.
Angina Pectoris↗
Afterload reduction with hydralazine following valve replacement.
Impedance reduction with hydralazine was evaluated in 23 patients 1 to 3 hours after aortic or mitral valve replacement. Patients were randomly assigned to Group 1 (0.25 mg/kg) or Group 2 (0.5 mg/kg) and responses at 20, 60, and 120 minutes compared with control (paired t test) and mean values for each group compared (t test). In Group 1 significant responses were the fall in mean arterial pressure (78.3 +/- 3.0 to 66.7 +/- 2.2 mm Hg) and systemic vascular resistance (2,808 +/- 264 to 1,823 +/- 164 dynes-sec/cm5); the increase in cardiac index (2.07 +/- 0.13 to 2.71 +/- 0.21 L/min/m2), stroke volume index (26.9 +/- 2.3 to 34.0 +/- 3.3 ml/beat), and heart rate (80.8 +/- 5.8 to 84.2 +/- 6.6 beats/min). Central venous pressure did not change and left atrial pressure decreased at 120 minutes. Group 2 responses were similar except for higher central venous pressure at 20 minutes, higher left atrial pressures at control, 20, and 60 minutes, and lower left ventricular stroke work at control, 20, and 60 minutes. By selectively dilating the arterial system, hydralazine reduces mean arterial pressure and systemic vascular resistance and increases cardiac output with suble filling pressures.
Aortic Valve↗
Revascularization of the right coronary artery.
This study was undertaken to evaluate revascularization of the right coronary artery with regard to factors that enter into the decision to graft less significant lesions, such as graft flow, graft patency and progression of proximal disease. The results of grafting the right coronary artery were studied in 23 patients with lesions reducing luminal diameter by less than 50 percent (Group 1), 35 patients with luminal narrowing of 50 to 70 percent (Group 2) and 112 patients with greater than 70 percent luminal narrowing (Group 3). At operation there was no significant difference in saphenous vein graft flows among the three groups. Postoperatively the mean follow-up period was 20, 27 and 26 months, respectively. Graft patency was not significantly different among the three groups. Progression of the proximal lesion was studied and compared with that in 71 ungrafted right coronary arteries, 60 with less than 50 percent stenosis and 11 with more than 50 percent stenosis. Among vessels with less than 50 percent narrowing, the proximal lesion showed progression in 26 percent of the ungrafted vessels and in 83 percent of the grafted vessels (P less than 0.005); progression to total occlusion occurred in 3 percent of the former and in 28 percent of the latter (P less than 0.005). Progression to total occlusion was more frequently associated with a patent than with an occluded graft (P less than 0.05). The occurrence of significant progression in ungrafted vessels and the lack of effect on graft patency of the severity of the proximal disease suggest that revascularization of less significant lesions may be of value. However, the resultant increase in progression of proximal disease makes the patient dependent on the long-term patency of the vein graft.
Cardiac Catheterization↗
Long-term results of myocardial revascularization.
During 1970 to 1977, among 1,733 patients who underwent isolated coronary bypass grafting, the operative mortality was 2.5 percent. Actuarial 5 year survival is 88.1 percent. At an average follow-up of 46 months (range 13 to 108), 90 percent of patients remain angina-free or with symptomatic improvement. The 5 year survival rate of patients with single vessel coronary artery disease is 97.9 percent. In patients with multivessel disease, operative survival appears to be favorably influenced by the presence of normal preoperative ventricular function. Late survival is significantly better in patients with multivessel disease with normal preoperative ventricular function or with complete revascularization. Risk of perioperative myocardial infarction has been appreciably reduced by the introduction of cold potassium chloride cardioplegia. Late myocardial infarction has occurred at an average annual risk of 1.46 percent. These data show that long-term survival and a small incidence of late myocardial infarction after myocardial revascularization are more likely in patients who undergo complete revascularization before significant left ventricular myocardial damage has occurred.
Adult↗
Evaluation of the results of external choledochoduodenostomy for retained, recurrent, or primary common duct stones.
Twenty-five patients were treated for retained, recurrent, or primary common duct stones by permanent drainage of the biliary tract with external choledochoduodenostomy. Twenty-one patients had common duct stones which became evident two to fifty years after the initial biliary tract procedure and which may represent stones formed in the common duct. Three recent patients had a clinical history of primary common duct stones, had stones which were soluble in chloroform-methanol solution, and had hepatic bile which was lithogenic as determined by evaluating the molar percentage of cholesterol, phospholipid, and bile salt in bile samples obtained at the time of choledochoduodenostomy. These data suggest that further stone formation is possible and that permanent bypass of the sphincter of Oddi is indicated to prevent recurrent bile duct obstruction. Long-term evaluation of the results of external choledochoduodenostomy indicates that the procedure is safe and effective in the prevention of recurrent biliary tract calculi.
Adult↗
Extremity revascularization: a decade of experience.
Operative management provides low risk palliation for symptomatic occlusive disease of the leg. Survival is adversely affected by associated conditions. The rate of limb salvage was 70 per cent at 2 years in patients with gangrene. Bypass grafting did not increase the risk of subsequent amputation (mortality 11 per cent), and therefore primary amputation should be avoided.
Adult↗
Ultrastructural integrity of human ventricular myocardium following cardioplegic arrest.
The appearance of the ventricular myocardium in 6 patients electing coronary bypass operation was evaluated by electron microscope before and after aortic cross-clamping. Bypassing protocol included the induction of hypothermic cardioplegia by intermittent aortic root perfusion, with potassium chloride added to cold blood serving as the cardioplegic agent. Cross-clamp intervals ranged from 66 to 125 minutes. Ultrastructural alterations following bypass manipulations, and distinct from those observed before cross-clamping, were limited to the presence of extensive myocardiocytic pooling of glycogen. Scrutiny of the intramyocardial capillary bed following perfusion with the cardioplegic solution revealed no abnormalities attributable to, or intensified by, the bypass maneuver. These findings indicate that hypothermic potassium cardioplegia, as specified, is not injurious to human myocardial ultrastructure.
Adult↗
Cold blood as the vehicle for potassium cardioplegia.
Cold blood with potassium, 34 mEq/L, was compared with cold blood and with a cardioplegic solution. Three groups of 6 dogs had 2 hours of aortic cross-clamp while on total bypass at 28 degrees C with the left ventricle vented. An initial 5-minute coronary perfusion was followed by 2 minutes of perfusion every 15 minutes for the cardioplegic solution (8 degrees C) and every 30 minutes for 3 minutes with cold blood or cold blood with potassium (8 degrees C). Hearts receiving cold blood or cold blood with potassium had topical cardiac hypothermia with crushed ice. Peak systolic pressure, rate of rise of left ventricular pressure, maximum velocity of the contractile element, pressure volume curves, coronary flow, coronary flow distribution, and myocardial uptake of oxygen, lactate, and pyruvate were measured prior to ischemia and 30 minutes after restoration of coronary flow. Myocardial creatine phosphate (CP), adenosine triphosphate (ATP), and adenosine diphosphate (ADP) were determined at the end of ischemia and after recovery. Changes in coronary flow, coronary flow distribution, and myocardial uptake of oxygen and pyruvate were not significant. Peak systolic pressure and lactate uptake declined significantly for hearts perfused with cold blood but not those with cold blood with potassium. ATP and ADP were lowest in hearts perfused with cardioplegic solution, and CP and ATP did not return to control in any group. Heart water increased with the use of cold blood and cardioplegic solution. Myocardial protection with cold blood with potassium and topical hypothermia has some advantages over cold blood and cardioplegic solution.
Adenosine Diphosphate↗
Ventricular function and the native coronary circulation five years after myocardial revascularization.
Of 531 patients who underwent coronary artery bypass grafting during 1970 to 1973, 181 were restudied by ventriculography and by graft and coronary angiography at least 5 years following operation. Five patterns of postoperative ventricular function were identified: improved ventricular function resulting in normal left ventricular (LV) function; normal ventricular function that was unchanged; abnormal ventricular function that improved but did not reach normal; abnormal ventricular function that remained unchanged; and deterioration of LV function. Patients who regained (40) and those who retained normal ventricular function (49) comprise 49% of the series and patients with deterioration of ventricular function, only 20%. Graft patency and angina relief were significantly better in those with normal LV function than in those with LV deterioration. Progression of disease in grafted coronary arteries was similar in all groups, but was significantly higher in ungrafted coronary arteries (61.3%) in the patients showing deterioration than in either the improved patients or those with an unchanged normal LV (33.3% each) (p less than 0.05). The high incidence of progression of disease in ungrafted coronary arteries in the group with deterioration suggests that low graft patency and deterioration of ventricular function in this group might both be related to intrinsic acceleration of coronary atherosclerosis unrelated to operative intervention.
Angina Pectoris↗
Esophageal atresia and tracheoesophageal fistula: preoperative assessment and reduced mortality.
One hundred twenty-nine infants with esophageal atresia and tracheoesophageal fistula were reviewed from 1955 to 1978. The overall mortality was 38%. Factors associated with the increased mortality include prematurity, pneumonia, and congenital defects other than this anomaly. A classification based on these factors in introduced, which provides the clinician with a prognostic survival rate greater than 90% with only physical examination, chest and abdominal roentgenography, and intravenous pyelography. Postoperative mortality was reduced to 11% in the last five years of the study; this is attributed to the exclusive use of the retropleural approach to the esophagus, more intensive postoperative ventilatory support, and routine use of parenteral nutrition.
Esophageal Atresia↗
Capillary basal laminar thichness in diabetic human myocardium.
Biopsied myocardial tissue was obtained from 24 patients electing coronary arterial bypass surgery who were divided into three groups: chemical diabetics (CD) with normal fasting blood sugar levels and incidentally encountered elevated glucose levels after sugar loading; overt diabetics (OD) requiring insulin treatment; and euglycemic, nondiabetic patients (ND) serving as a control group. Specimens from the left anterior apical segment of the heart were processed for ultrastructural examination, with special emphasis on determining capillary basal laminar thickness with the aid of morphometric techniques. Results of this study indicate that (1) a statistically significant increase in basal laminar thickness is evident in myocardial tissue of OD patients; (2) incipient alterations in laminar width are demonstrable in the CD group; (3) the predominant morphologic abnormalities, which we have examined in the parenchymal tissue of the biopsied hearts, namely myocardial hypertrophy and interstitial fibrosis, are present to a comparable degree in all three groups of patients; and (4) the average thickness of basal laminae around myocardial capillaries tends to be narrower compared with measurements reported in other tissue compartments.
Adult↗
Supraventricular tachyarrhythmias after myocardial revascularization: a randomized trial of prophylactic digitalization.
The success of prophylactic digitalization in reducing the incidence of supraventricular tachyarrhythmias (SVT) was studied in 140 randomly grouped, consecutive patients undergoing myocardial revascularization operations. The test group received either 1 or 1.5 mg. of digoxin the day before operation and were maintained postoperatively on 0.25 mg. of digoxin daily. There was a significant increase (p less than 0.05) in the incidence of SVT in the treated patients (17 of 61 or 27.8 percent) vs. the untreated patients (nine of 79 or 11.4 percent). There was no significant difference in SVT with the two digitalization dosage levels (31.6 percent with 1 mg. vs. 21.7 percent with 1.5 mg.). Prophylactic digitalization demonstrates no benefit in the prevention of SVT following myocardial revascularization and may, in fact, predispose the patient to these arrhythmias.
Coronary Artery Bypass↗