Occlusion of Björk-Shiley aortic valve prosthesis by hypertrophied ventricular septum.
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Aged↗
Biomedical subjects
G N Olinger
Publications and source records attributed to G N Olinger.
Aspirin or dipyridamole individually prevent lipid accumulation in primate vein bypass grafts.
Although platelet inhibition with both aspirin and dipyridamole is widely prescribed for patients with coronary artery bypass grafts, data are lacking to prove that combined drug therapy has greater efficacy in preserving graft integrity than either drug given independently. Thus, the ability of combined vs single drug therapy to reduce cholesterol and apolipoprotein-B accumulation were compared in autologous cephalic veins grafted into femoral arteries of 23 stump-tailed macaque monkeys. Ten monkeys were studied in 2 phases. They were treated with aspirin (80 mg/day) during 1 phase and with dipyridamole (50 mg/day) during the other phase. Five monkeys received aspirin plus dipyridamole in combination and 8 received no medication and served as controls. When grafts were removed 3 months after insertion cholesterol and apolipoprotein-B concentrations in grafts were similar for groups treated with aspirin, with dipyridamole, and with the drugs combined, and in each of the treated groups these concentrations were significantly reduced compared with grafts from untreated control monkeys. Cholesterol and apolipoprotein-B concentrations in grafts from the treated groups were similar to concentrations in normal ungrafted veins, whereas cholesterol and apolipoprotein-B levels in grafts from control monkeys were significantly greater than those in ungrafted veins (250% and 925% of normal, respectively). Our findings reaffirm the ameliorative effect of anti-platelet drugs in reducing the accumulation of lipid in vein bypass grafts and indicate that the efficacy of aspirin or dipyridamole given individually equals that of the combination of these drugs in this subhuman primate model. The relation of the lipid-lowering effect of these agents to their antithrombotic effect is uncertain.
Animals↗
Long-term follow-up of survivors of prehospital sudden cardiac death treated with coronary bypass surgery.
Although coronary artery bypass surgery is beneficial to patients with severe coronary artery disease, its role in preventing the recurrence of prehospital cardiac arrest in patients is not clear. In this article, we report on the long-term follow-up of 49 survivors of prehospital coronary arrest who had coronary artery bypass surgery. Prior to their prehospital cardiac arrest, 14% of the patients had a history of unstable angina. Coronary angiograms obtained after prehospital cardiac arrest showed that 71% of the patients had three-vessel coronary artery disease and 6% had single-vessel disease. The mean left ventricular ejection fraction was 45%. There were four postoperative deaths; three were caused by pump failure, and one was caused by refractory ventricular arrhythmias. After a maximum follow-up period of 102 months (mean of 55.4 months), there were seven cardiac deaths; five of the patients died of recurrent ventricular fibrillation, and two patients' deaths were related to refractory heart failure. Actuarial analyses of the 49 patients showed that the probability of survival at 6 months, 1 year, 2 years, 3 years, and 5 years was 92%, 92%, 89%, 82%, and 72%, respectively. After surgery, 35 of the 45 patients who were discharged from the hospital were asymptomatic, and 23 of the 32 patients who were employed when their prehospital cardiac arrest occurred returned to their employment. We concluded that coronary artery bypass surgery is beneficial to certain survivors of prehospital sudden death. After surgery, most patients are asymptomatic and capable of returning to their employment and the recurrence of prehospital sudden death is low.
Aged↗
Mitral valve prolapse requiring surgery. Clinical and pathologic study.
The clinical, hemodynamic, surgical, and pathologic findings in 30 patients who required mitral valvular surgery and who had a preoperative diagnosis of mitral valve prolapse were reviewed. The mean age of the patients was 59.5 years; 28 patients were over 45 years of age and 10 were over 60 years. Surprisingly, 20 were males. A long history of systolic murmur was common, whereas symptoms of heart failure were of abrupt onset. At the time of surgery, a local holosystolic murmur typical of mitral regurgitation was present, although a mid- to late systolic click was not heard in any of the patients. Electrocardiographic abnormalities were present in all patients, with 13 patients demonstrating atrial fibrillation. Only four patients had a normal heart size radiographically. Echocardiography confirmed the radiographic findings, in that 27 patients demonstrated left atrial and ventricular enlargement. All 29 patients undergoing cardiac catheterization and angiography demonstrated a prolapsing mitral valve with severe regurgitation. Surgical and pathologic examination revealed findings characteristic of a myxomatous valve in all patients, with 19 also demonstrating ruptured chordae tendineae. This study demonstrates that heart failure requiring valvular surgery occurs in a subset of patients with mitral valve prolapse. In this subset, males predominate and most are over 50 years of age. These patients may be asymptomatic for many years, demonstrating mild to moderate mitral valvular regurgitation, before heart failure develops.
Adult↗
The implanted defibrillator: relation of defibrillating lead configuration and clinical variables to defibrillation threshold.
Forty-two defibrillating lead systems for the automatic implantable defibrillator were implanted and tested in 41 patients. Two basic lead configurations were used: 1) spring-patch, consisting of a transvenous superior vena cava spring electrode as the anode and an apical or left lateral ventricular patch electrode (either small [13.9 cm2] or large [27.9 cm2]) as the cathode; and 2) patch-patch, consisting of an anterior right ventricular patch as the anode and a posterior left ventricular patch as the cathode. Of the 42 lead systems, 10 were spring-patch and 32 were patch-patch combinations. The defibrillation threshold for the patch-patch combinations (9.8 +/- 6.5 J, mean +/- standard deviation) was significantly (p less than 0.01) lower than that for the spring-patch combinations (19.1 +/- 10.3 J). Subgroup analysis revealed the lowest defibrillation thresholds for patch-patch combinations with at least one large patch. Total surface area of defibrillating leads was strongly negatively correlated with the defibrillation threshold (p less than 0.005). Analysis of the relation of clinical variables to defibrillation threshold revealed that only amiodarone therapy was independently associated with a significantly (p less than 0.05) higher defibrillation threshold. Thus, surface area of the defibrillating leads is a critical determinant of the defibrillation threshold for the implanted defibrillator. Patch-patch lead systems with at least one large patch may provide an increased safety margin for defibrillation. Conversely, amiodarone therapy is associated with higher defibrillation thresholds and may decrease the margin of safety.
Adolescent↗
Standardization of end-systolic pressure-volume relation in the dog.
Left ventricular (LV) volume elastance (Emax) and its volume intercept (Vo) are subject to considerable intersubject and interspecies variation. In humans, indexing with body surface area does not decrease variance. Because these are volume indexes, it was considered they would better standardize against body or LV weight. Fifteen open-chest mongrel dogs (mean wt 25.9 +/- 8.0 kg, range 15.6-42.5) were studied under 1% halothane anesthesia. Emax, derived by caval occlusion, averaged 9.0 +/- 4.4 mmHg X ml-1 (range 4.1-16.1) with a coefficient of variation (CV) of 48%. Average Vo was 19.6 +/- 10.5 ml (range 8.3-40.3) with a CV of 53%. LV weight was 110 +/- 21 g (range 78-147). Vo correlated best with LV weight: Y = 0.47 X - 31.78, r = 0.93, and adjustment of Vo by regression reduced CV to 20%. Emax was closely correlated with either 1/dog wt [Y = 313.02 (1/X) - 4.16, r = 0.88, CV = 23% after adjustment by regression] or 1/LV wt [Y = 2088.63 (1/X) - 10.72, r = 0.86, CV = 25% after adjustment]. Indexing of Emax by dog weight (CV = 29%) or LV weight (CV = 35%) reduced variation but by less than adjustment by regression. A subset of eight dogs had inotropic state varied, which had no effect on the relation between Vo and LV weight, but which resulted in an appropriate change (P less than 0.025) in the relation between Emax and 1/LV wt.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Aspirin and dipyridamole reduce lipid accumulation in vein bypass grafts: combination versus single drug therapy.
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Animals↗
The relative influence of arterial pressure versus intraoperative distention on lipid accumulation in primate vein bypass grafts.
Atherosclerotic degeneration has been well documented to be the limiting factor for long-term function of aortacoronary vein bypass grafts. Injury, including that induced by pressure distention in preparation for grafting, is thought to play a role in this degeneration. Injury can be minimized by limiting the distending pressure, but vein grafts are chronically subjected to arterial pressures that far exceed native venous pressure. We evaluated the relative influence of arterial pressure and of higher pressure of distention on cholesterol and apolipoprotein-B accumulation by grafts in our established animal model of graft atherogenesis. Grafts were interposed in the femoral arteries of eight normolipemic stump-tailed macaque monkeys. Before insertion, each vein was distended at 125 mm Hg (arterial pressure) for 1 minute with autologous blood, followed by distention of one half of the vein at 350 mm Hg for 1 additional minute. Grafts and ungrafted control vein were removed 3 months later. Cholesterol concentration in grafts distended at 125 mm Hg was 213% (p less than 0.01) and apolipoprotein-B concentration was 430% (p less than 0.001) of that in ungrafted control veins, whereas in grafts distended at 350 mm Hg cholesterol was 250% (p less than 0.01) and apolipoprotein-B was 925% (p less than 0.001) of the control concentrations. Although morphologic differences between the two groups of grafts were less profound than biochemical differences, foam cells were observed more frequently in grafts distended at 350 mm Hg than in those distended at 125 mm Hg. These data demonstrate that chronic exposure to arterial pressure has a significant effect on graft cholesterol that is proportionally greater than that caused by intraoperative distention at moderate pressure. Nevertheless, the detrimental effects of excessive distending pressures should not be ignored.
Animals↗
Papaverine irrigation of vein grafts.
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Humans↗
Mitral valve replacement in idiopathic hypereosinophilic syndrome.
Idiopathic hypereosinophilic syndrome is a rare systemic disease that can cause one form of endocardial fibrosis. Endocardial fibrous tissue with overlying thrombus formation in idiopathic hypereosinophilic syndrome leads to a restrictive cardiomyopathy that may produce mitral and/or tricuspid regurgitation. This report describes a patient with idiopathic hypereosinophilic syndrome who underwent mitral valve replacement and successful steroid therapy for an usually localized form of endocardial fibrosis.
Endocarditis↗
Operative approach to endocarditis.
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Adult↗
Long-term survival after prehospital sudden cardiac death.
One hundred thirty-nine survivors of prehospital sudden cardiac death were followed after their hospital discharge. Eighty patients were studied with coronary angiography and cardiac catheterization; 34 of these underwent coronary bypass surgery. After a maximum follow-up of 105 months, 89 patients were still alive. The probability of survival at 6 months, 1 year, 2 years, 3 years, 4 years, and 5 years was 88%, 86%, 78%, 70%, 63%, and 59%, respectively. Of the 43 cardiac deaths, 37 (86%) were secondary to documented recurrent ventricular fibrillation or occurred suddenly. Twelve percent of the total population had recurrent ventricular fibrillation in the first year following the initial cardiac arrest, 16% within 2 years, and 22% within 3 years. Of the 37 survivors dying from recurrent ventricular fibrillation, 32% died within the first 3 months following hospital discharge, 46% in the first year, 64% within 2 years, and 78% within the first 3 years. Most survivors were capable of resuming normal activities after hospital discharge. Only 7% demonstrated permanent neurologic impairment. Sixty-eight percent of the patients who were employed at the time of their prehospital sudden cardiac arrest returned to full-time employment. In the subset of 34 surgically treated patients, there have been six (18%) cardiac deaths. Four of these deaths were related to recurrent ventricular fibrillation, with one of these deaths occurring in the immediate postoperative period. The other three deaths related to recurrent ventricular fibrillation occurred 36 months (two deaths) and 49 months following the initial prehospital cardiac arrest.
Adolescent↗
Cardiopulmonary bypass for patients with previously documented heparin-induced platelet aggregation.
Heparin-dependent intravascular coagulation is a widely recognized syndrome in which heparin acts as a hapten for an antiplatelet antibody and causes accelerated intravascular thrombosis and thrombocytopenia that may culminate in organ loss, hemorrhagic diathesis, and even death. Diagnosis is made in vitro by observing heparin-stimulated aggregation of normal platelets suspended in the patient's platelet-poor plasma. Treatment consists of cessation of heparin and use of antiaggregating agents with or without warfarin sodium. Management of patients with prior heparin-dependent intravascular coagulation who require cardiopulmonary bypass has not been reported. We now have successfully managed three such patients and herein present guidelines for management. Each patient was undergoing heparin therapy and manifested hallmark heparin tachyphylaxis, thrombocytopenia, and increased thrombotic symptoms (further venous thrombosis after cardiac catheterization in two cases and exacerbation of unstable angina in the other). In vitro aggregation studies were abnormal. Heparin was stopped, and antiaggregative therapy was begun with good response in each instance. In vitro studies were done serially until the antiplatelet antibody reaction had vanished (usually 4 to 8 weeks), and coronary revascularization was then conducted with full heparinization. Further heparin exposure postoperatively was avoided. There was no perioperative evidence of intravascular thrombosis or bleeding diathesis, and in vitro heparin-dependent aggregation did not recur. We conclude that patients with previously documented heparin-dependent intravascular coagulation can safely sustain the massive heparin rechallenge of cardiopulmonary bypass, provided that in vitro aggregation has ceased and rechallenge therapy is not prolonged.
Aged↗
Left ventricular performance after mitral reconstruction for mitral regurgitation.
Depressed left ventricular performance is often observed after mitral valve replacement for mitral regurgitation and is generally attributed to increased impedance to left ventricular ejection. We analyzed preoperative and postoperative catheterization data in 10 of 18 patients who underwent mitral reconstruction with preservation of the native valves and found a significant (p less than 0.05) fall in left ventricular end-diastolic volume index (from 143 +/- 39 to 84 +/- 21 ml/m2) and end-systolic volume index (from 50 +/- 24 to 32 +/- 12 ml/m2), with no significant change in ejection fraction (0.66 +/- 0.1 versus 0.62 +/- 0.1). These findings contrast with studies reported by others in comparable patients who had mitral valve replacement with no improvement in volume indices and a decline in ejection fraction postoperatively. We suggest that some of the left ventricular dysfunction observed after mitral replacement may be due simply to excision of the native valve. Mitral repair retains the tethering effect of chordal attachments and may thus prevent postoperative left ventricular dilatation and moderate the increase in wall stress that results from increased impedance to left ventricular ejection.
Adult↗
Noninvasive evaluation of a left ventricular pseudoaneurysm: complementary role of echocardiographic and nuclear techniques.
This 45-year-old white male was evaluated for congestive heart failure initially ascribed to a rapidly progressive cardiomyopathy. Both radionuclide ventriculography and echocardiography correctly identified a left ventricular pseudoaneurysm as the cause for heart failure. Thallium-201 scintigraphy, by demonstrating a large perfusion defect, suggested a large ostium of the pseudoaneurysm. Following resection of the false aneurysm, a Dacron prosthesis was required to close a large posterior wall defect. We conclude that both radionuclide ventriculography and echocardiography can independently demonstrate a left ventricular pseudoaneurysm. The combined noninvasive approach is able to delineate various anatomical aspects of the pseudoaneurysm and help in planning adequate surgical intervention.
Cardiac Catheterization↗
Removal of percutaneous intraaortic balloon.
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Aorta↗
Pulsatile cardiopulmonary bypass for patients with renal insufficiency.
Pulsatile cardiopulmonary bypass has been shown to preserve renal function and could therefore have considerable clinical value in patients undergoing cardiac surgery with preoperative renal insufficiency, by protecting them from further postoperative renal deterioration. Our three-year experience with pulsatile bypass in 29 patients with a preoperative serum creatinine concentration over 1.7 mg/100 ml (mean 2.9, range 1.8-6.1 mg/100 ml) (greater than 150 mumol/l (mean 256, range 159-539 mumol/l] supports this premise. There were no renal deaths in the perioperative period and only two patients had irreversible postoperative deterioration in renal function; one died on day 3 of low-output syndrome and the other had rapidly progressive nephrosclerosis and died of that disease one year later. Postoperative oliguria occurred in the patient with low cardiac output and in only one other. This experience contrasts with our previous experience and that reported by others with non-pulsatile bypass in patients with renal insufficiency. We suggest that pulsatile bypass should be considered for cardiac surgery in patients with preoperative renal dysfunction.
Adult↗
Hyperkalemia in cardioplegic solutions causing increased cholesterol accumulation in vein grafts.
Hyperkalemic cardioplegic solutions are frequently infused through vein grafts during aorta-coronary bypass operations. Although some reports have suggested the potential for physical damage to grafts by such exposure, the effects of these solutions on graft atherogenesis have not been studied. We evaluated the influence of potassium and colloid content of cardioplegic solutions on graft cholesterol accumulation in our established animal model of graft atherogenesis. Fourteen cephalic vein grafts were interposed bilaterally in the femoral arteries of seven normolipemic stump-tailed macaque monkeys. Before grafting, each vein was distended at 350 torr for 1 minute with autologous blood. Half of each vein was then filled for 30 minutes with either balanced crystalloid solution or with balanced crystalloid plus albumin (5 mg/ml). The other half of the vein was filled with the same solution plus potassium chloride (27 mEq/L). Grafts were harvested at 12 weeks. Cholesterol content was significantly greater (p less than 0.01) in graft segments exposed to hyperkalemia than in their control counterparts. Onconicity had no effect on cholesterol content. In this animal model, prolonged exposure of vein grafts to hyperkalemic cardioplegic solutions caused increased lipid uptake. This finding may presage accelerated atheromatous degeneration.
Animals↗