Biomedical subjects

J R Pluth

Publications and source records attributed to J R Pluth.

At least 37 records · Page 2Linked to original sources

PubMed1987

Repair of ascending aortic dissection. Influence of associated aortic valve insufficiency on early and late results.

Operative treatment of dissections of the ascending aorta differs from that for the descending aorta, not only because of the need for cardiopulmonary bypass, but also because of the frequent occurrence of aortic valve insufficiency. To determine the early and late results of operative repair, we have reviewed the case histories of 121 consecutive patients who underwent repair of ascending aortic dissections between 1962 and 1985. Ages ranged from 16 to 79 years (mean 56 +/- 14 years); 54 patients had operation within 2 weeks of onset of symptoms (acute), and the remainder had later repair (chronic). Seventy patients (58%) had clinical evidence of aortic insufficiency at the time of admission. During repair of acute dissection, 10 patients (19%) had aortic valve resuspension and 15 patients (28%) had aortic valve replacement. During repair of chronic dissection, eight patients (12%) had resuspension and 43 patients (64%) had replacement. Overall operative mortality was 22%, significantly higher for patients with acute than for those with chronic dissections (39% versus 9%, p less than 0.01). Operative risk was similar for patients who underwent repair of ascending aortic dissections without valve resuspension or replacement (31%) versus those who had repair with aortic valve resuspension (17%) or replacement (17%). During a follow-up period ranging from 1 to 208 months, aortic regurgitation developed in only two patients who did not have aortic insufficiency at the time of repair. Late aortic regurgitation necessitating reoperation developed in one of the 15 survivors who had aortic valve resuspension. Eight patients undergoing aortic valve replacement had complications of their prostheses, including one periprosthetic leak and four mechanical failures. We conclude that resuspension or replacement of the aortic valve does not increase the risk of repair of ascending aortic dissections. Selective management of aortic insufficiency (with valve repair whenever possible) yields satisfactory long-term results.

Aortic Dissection↗

PubMed1986

Superoxide generation during cardiopulmonary bypass: is there a role for vitamin E?

The cytotoxic metabolites of oxygen [superoxide (O-2), hydrogen peroxide (H2O2), and hydroxyl (OH.)] have been demonstrated to be involved in the peroxidation of membrane lipids consequently altering membrane composition, morphology, and function. Of all the lines of defense adopted by living organisms against toxic oxygen free radicals, vitamin E is most effective in the prevention of membrane damage. Cardiopulmonary bypass (CPB) has been shown to activate complement and cause sequestration of leukocytes which can recruit, adhere, and stimulate release of cytotoxic oxygen radicals. A prospective study of 30 patients evaluated the effects of CPB with and without an exogenous free radical scavenger (Group I, N = 20, control) and (Group II, N = 10, vitamin E) on H2O2 (a marker of oxygen free radicals) malonaldehyde (a marker of lipid peroxidation), transpulmonary leukosequestration, and plasma levels of vitamins E and C. Group I showed a progressive increase in H2O2 during CPB from 65 +/- 6 to 130 +/- 11 micron/ml (P less than 0.0001); plasma vitamin E decreased from 15 +/- 3 to 6 +/- 1 mg/liter (P less than 0.0001) while vitamin C increased from 1.6 +/- .3 to 2.3 +/- .3 mg/dl (P less than 0.0001). Group II showed no significant increase in H2O2 (from 78 +/- 8 to 93 +/- 5 microns/ml) during CPB and a significant reduction in H2O2 levels compared to Group I (P less than 0.001); plasma vitamins E and C did not change significantly in Group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Ascorbic Acid↗

PubMed1986

Mechanical decalcification of the aortic valve.

Thromboembolism and anticoagulant-related complications secondary to prosthetic aortic valve replacement constitute a significant risk (28% at 5 years). From 1978 through 1984, decalcification of the aortic valve was performed in 8 patients who were undergoing coronary artery revascularization. Preoperative gradients of between 30 and 80 mm Hg (mean, 50 mm Hg) were abolished after operation. To determine the viability of decalcification, the records of 84 additional patients who had undergone this procedure between 1959 and 1978 were reviewed (86% before 1965). There were 60 male and 32 female patients ranging from 14 to 74 years old (mean, 49 years). The cause of the calcification was a bicuspid valve in 32 patients (35%), senile calcification in 9 (10%), and rheumatic fever in 50 (54%); the cause in 1 patient was unknown. Thirty-day mortality was 13%. Follow-up was 98% complete and ranged from 6 months to 22 years (mean, 7 years). Aortic valve replacement was subsequently required in 25 patients. Freedom from reoperation at 1, 5, 10, and 15 years was 98%, 75%, 43%, and 26%, respectively, for patients with rheumatic valves compared with 97%, 76%, 57%, and 51%, respectively, for those with bicuspid valves. Survival for patients with rheumatic valves at 1, 5, 10, 15, and 20 years was 93%, 70%, 48%, 40%, and 35%, respectively, compared with 100%, 66%, 57%, 46%, and 46% for patients with bicuspid valves. At follow-up, 61% of the patients were in New York Heart Association Functional Class I or II. Causes of late death were valve related (30%), congestive heart failure (27%), and myocardial infarction (24%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1986

Coronary artery venous bypass graft aneurysm with symptomatic coronary artery emboli.

A 53 year old man, asymptomatic for 9 years after aorto-right coronary artery venous bypass surgery, developed two prolonged episodes of myocardial ischemia during a 7 month interval. Diagnostic exercise tests subsequent to each episode were normal. Coronary angiography demonstrated marked dilation with filling defects of the venous bypass graft. A large thrombus-filled venous bypass graft aneurysm was excised at surgery. Spontaneous coronary artery embolization related to a venous bypass graft aneurysm has not been described previously, but may become more frequent as survival and follow-up after coronary bypass surgery lengthen.

Aneurysm↗

PubMed1986

Early and late results following repair of dissections of the descending thoracic aorta.

Management of dissections of the descending thoracic aorta remains controversial, especially with regard to timing and method of repair. To clarify these and other issues we have reviewed our total experience with repair of descending aortic dissections between 1962 and 1983. The 44 men and 20 women had a mean (+/- SEM) age of 59 +/- 2 years (range, 19 to 83 years), and in all patients the dissection originated in and was limited to the aorta distal to the left carotid artery (Stanford type B, DeBakey types IIIa and IIIb). Twenty-nine patients underwent operation within 2 weeks of the onset of symptoms (acute), and the remainder had later repair (chronic). During repair, circulation distal to the aortic cross-clamp was supported with cardiopulmonary bypass or shunt in two thirds of patients. Overall, 18 deaths occurred less than or equal to 30 days postoperatively (operative risk 28%), and risk was higher in acute (45%) than in chronic (14%) dissections. Operative risk was not significantly related to protection of the distal circulation. The most serious postoperative complication was spinal cord ischemia manifested by paraplegia in five patients (8%) and transient or permanent paraparesis in six patients (9%). Risk of spinal cord ischemia was significantly lower in patients who had protection of the distal circulation during operative repair (8% vs. 44%, p = 0.003). Late survival, including hospital deaths, was 49% +/- 7% at 5 years after operation; 22 of the 46 patients who survived repair were found to have aneurysms involving the thoracic and/or abdominal segments of the aorta. Our results indicate that repair of chronic dissection of the thoracic aorta has a lower operative risk than repair of acute dissections, and initial medical management of acute dissection may be indicated if no early complications occur. Risk of spinal cord ischemia is significantly reduced by cardiopulmonary bypass or shunt and is preferred over aortic cross-clamping alone. Finally, these patients require careful long-term follow-up because of the high incidence of residual or recurrent aortic aneurysms.

Acute Disease↗

PubMed1986

Concomitant mitral valve repair or replacement and coronary revascularization.

Patients undergoing combined mitral valve replacement and coronary revascularization require surgical skill and especially judgment for optimal results. In our hands, cardioplegia has not been a pivotal event in affecting survival, and this probably relates to our previous philosophy of limiting the hypothermic ischemic episodes to 15-minute intervals. Currently, we believe that valve repair, when it can be accomplished, is preferable to valve replacement, especially in the patient with ischemic mitral valve disease. When repair cannot be satisfactorily accomplished, replacement with retention of the posterior leaflet seems clinically to be associated with less disturbance of left ventricular function.

Anesthesia↗

PubMed1986

Influence of antioxidants (mannitol and allopurinol) on oxygen free radical generation during and after cardiopulmonary bypass.

Oxygen-derived free radicals (O2-, H2O2, OH.) are produced during oxidative metabolism, ischemia and reperfusion, and cardiopulmonary bypass (CPB). When oxygen free radical production exceeds scavenging capacity, peroxidation of structural lipids in cell membranes can occur with potentially injurious consequences. In this prospective study, 45 patients were evaluated to determine the effect of CPB on oxygen free radical generation. Twenty patients in group I were controls. Exogenous oxygen free radical antioxidants were administered before bypass to patients in group II (n = 15, mannitol) and group III (n = 10, allopurinol). In group I, plasma H2O2 increased during extracorporeal circulation from 65 +/- 6.0 to 125 +/- 12 microM/ml (p less than .001). At similar sampling intervals, plasma H2O2 levels were significantly lower in group II (p less than .03) and group III (p less than .05) when compared with those in group I. Red blood cell H2O2 did not change in group I or group II. White blood cell H2O2 levels decreased in group I (p less than .04) and group II during CPB. (Intracellular concentrations of H2O2 were not obtained in group III patients). We conclude that cytotoxic oxygen radicals are generated during CPB and that pretreatment with free radical antioxidants, mannitol or allopurinol, may minimize the free radicals available for lipid peroxidation of biomembranes.

Allopurinol↗

PubMed1986

Complement activation during cardiopulmonary bypass. Comparison of bubble and membrane oxygenators.

A prospective randomized trial involving 91 patients undergoing cardiopulmonary bypass compared the effects of bubble oxygenators (with and without methylprednisolone sodium succinate) and membrane oxygenators on complement activation and transpulmonary sequestration of leukocytes. Patients were divided as follows: Group I, 30 patients, bubble oxygenator; Group II, 31 patients, bubble oxygenator and methylprednisolone sodium succinate (30 mg/kg); Group III, 30 patients, membrane oxygenator. In Group I, C3a increased from 323 +/- 171 ng/ml during cardiopulmonary bypass to 1,564 +/- 785 ng/ml at 25 minutes after bypass (p less than 0.0001). A significant decrease in C3a was found in Groups II and III compared to Group I (p less than 0.0001). C5a did not change significantly during cardiopulmonary bypass in any group. Reestablishment of pulmonary circulation at the end of bypass produced significant transpulmonary leukocyte sequestration in Group I; the median cell difference was 1,700/microliter. Transpulmonary sequestration was significantly (p less than 0.0001) less in Group II (median cell difference = 200/microliter) and in Group III (median cell difference = 400/microliter) than in Group I. We conclude that cardiopulmonary bypass with a bubble oxygenator alone initiates significantly (p less than 0.0001) more C3a activation and leukocyte sequestration than when methylprednisolone sodium succinate (30 mg/kg) is given 20 minutes before the start of cardiopulmonary bypass with a bubble oxygenator or when a silicone membrane oxygenator is used.

Adrenal Cortex Hormones↗

PubMed1986

Oxygen free radical generation during cardiopulmonary bypass: correlation with complement activation.

To determine the relationships among complement activation, pulmonary leukosequestration, and oxygen free radical generation, we prospectively studied 15 patients undergoing cardiopulmonary bypass for myocardial revascularization. Plasma levels of C3a, C4a, and hydrogen peroxide (a marker of oxygen free radical generation) were measured before, during, and after extracorporeal circulation. The results confirm that cardiopulmonary bypass activates complement via the alternate (C3a) pathway. This first phase of complement activation was accompanied by an increase in plasma H2O2 (from 80 +/- 8 to 155 +/- 13 microM/ml; p less than .001) and by pulmonary sequestration of polymorphonuclear leukocytes. Protamine administration after cardiopulmonary bypass further activated complement via the classical (C4a) pathway but was not accompanied by a change in plasma hydrogen peroxide. We hypothesize that both complement activation and excess oxygen free radical generation contribute to the pathophysiology of extracorporeal circulation.

Blood Cells↗

PubMed1986

The significance of multiple, recurrent, and "complex" cardiac myxomas.

We reviewed the Mayo Clinic records of 56 patients who underwent operation for cardiac myxoma and 29 cases in which cardiac myxoma was found at autopsy. Five patients had a "complex" of unusual findings including multiple pigmented skin lesions (lentiginosis), myxoid fibroadenomas of the breast, skin myxomas, and primary pigmented nodular adrenocortical disease (a cause of Cushing's syndrome). Four of these five patients had multiple cardiac myxomas. Three of the four patients who underwent surgical excision of the cardiac myxomas had recurrent myxomas (the only recurrences in our series), and one of these patients had a second recurrence. The occurrence of multiple and recurrent myxomas in patients with the complex was significantly (p less than 0.001) higher than in our 80 patients with sporadic myxomas. The world literature was searched for cases of cardiac myxomas with the unusual associations of the complex, and also for familial, multiple, and recurrent myxomas. A group of patients were identified who had unusual biologic behavior including early development of myxomas, atypical myxoma locations, and a high risk for the development of recurrent myxomas. For these patients, we recommend a thorough search for multiple tumors at operation, close postoperative follow-up, and careful screening of family members.

Adenofibroma↗

PubMed1985

Left ventricular outflow tract obstruction related to a valve prosthesis: case caused by a low-profile mitral prosthesis.

Mechanical and bioprosthetic mitral prostheses may have many potential complications. In patients with isolated mitral stenosis and a small left ventricular cavity, low-profile prostheses are recommended to avoid myocardial impingement that can result from a high-profile valve and lead to possible left ventricular inflow or outflow obstruction or ventricular arrhythmias. This case report illustrates that left ventricular outflow obstruction may also result from a low-profile mitral valve prosthesis. This obstruction was not diagnosed before cardiac catheterization. Assessment of patients with suspected prosthetic valve dysfunction is difficult and may necessitate cardiac catheterization or even direct surgical inspection for conclusive information.

Adult↗

PubMed1985

Results of triple valve replacement in 91 patients: perioperative mortality and long-term follow-up.

Between 1961 and 1984, 91 patients underwent simultaneous triple valve replacement at the Mayo Clinic. Of the 273 prosthetic valves used, 77% were Starr-Edwards. Perioperative (30 day) mortality was 24% to 27% between 1962 and 1974 and 7% between 1975 and 1983 (p = .17). In patients with NYHA class IV symptoms, perioperative mortality was 44%, and in those with milder symptoms, it was 8% (p less than .0001). The median follow-up was 7.5 years (range, 6 weeks to 20 years). Cumulative survival, which was calculated taking into consideration perioperative mortality, was 64% at 1 year, 55% at 5 years, 40% at 10 years, and 25% at 15 years. Multivariate analysis identified preoperative functional class and age as predictors of late survival. Among causes of late mortality were sudden death in 32.5%, congestive heart failure in 15%, thromboembolism in 12.5%, prosthetic valve dysfunction in 7.5%, and infective endocarditis in 5%. Late complications included systemic emboli in 42% (embolic rate, 12.3 events per 100 patient-years), bleeding in 22%, myocardial infarction in 16%, and infective endocarditis in 6%. Eight patients required reoperation for prosthetic valve dysfunction, and 12 patients had permanent pacemakers. Of the 29 patients still alive, 79% are in NYHA class I or II. In summary, perioperative mortality after triple valve replacement appears to be declining; long-term survival in 30 day survivors is similar to that after single valve replacement and excellent symptomatic improvement can be obtained, although morbidity is high.

Aortic Valve↗

PubMed1985

Evidence for complement activation by protamine-heparin interaction after cardiopulmonary bypass.

Complement activation by the alternate pathway has been implicated in the pathophysiology of cardiopulmonary bypass (CPB), and laboratory studies suggest that the complement cascade may be activated by the protamine-heparin complex. To determine if the administration of protamine to patients receiving heparin activates complement, we studied 100 patients undergoing CPB by assaying levels of C3a and C4a (classic pathway) at regular intervals before and after protamine administration. In group I (90 patients), protamine was given at the usual interval (median 5 minutes) after CPB. In group II (10 patients), protamine was withheld until skin closure (median 45 minutes) after CPB. Results demonstrated that C4a was not activated during CPB in either group. After CPB, the C4a level in group I was 459 ng/dl and increased to 1047 ng/dl 10 minutes after protamine administration (p less than 0.001). In group II, the C4a level was 484 ng/dl at the end of CPB and 354 ng/dl 15 minutes later, which corresponds to the value immediately after protamine administration in group I. The delayed administration of protamine in group II caused a significant increase in C4a at the time of skin closure (1090 ng/dl; p less than 0.001). Corresponding results from C3a analysis before and after protamine administration confirmed the activation of complement cascade. Our study provides the first clinical evidence that the protamine-heparin complex activates complement via the classic (C4a) pathway. The hemodynamic effects of protamine after CPB may be related to complement activation.

Aged↗

PubMed1985

Early and late results of pericardiectomy for constrictive pericarditis.

Records of 231 patients (171 males, 60 females; aged 10 months to 83 years [median 45 years]) who underwent operation for constrictive pericarditis at the Mayo Clinic from 1936 through 1982 were reviewed. All had had hemodynamically significant pericardial constriction preoperatively, and pericardial disease was confirmed at operation. Preoperatively, 69% were in New York Heart Association Class III or IV and 81% had peripheral edema or ascites. Pericardiectomy was performed through a left anterolateral thoracotomy (34%), a median sternotomy (27%), a U incision (Harrington) (21%), or a bilateral anterior thoracotomy (18%). Postoperatively, 28% of patients had evidence of low cardiac output; 70% of the 32 deaths within 30 days of operation were due to low cardiac output. Operative risk was significantly (p less than 0.001) related to preoperative disability (1% for Class I or II; 10% for class III; 46% for Class IV). Median postoperative follow-up was 9 years (longest was 43 years). Probability of survival for patients dismissed alive from the hospital was 84% at 5 years, 71% at 15 years, and 52% at 30 years. Long-term survival (excluding operative mortality) was not significantly influenced by the disability class preoperatively, the operative approach, or the development of low cardiac output in the immediate postoperative period. At the end of the follow-up interval, there were 141 patients in whom functional capacity could be assessed; 140 were in Class I or II. We conclude that a poor hemodynamic result after complete pericardiectomy relates to the preoperative degree of constriction and resultant cardiomyopathy. We recommend early pericardiectomy when pericardial constriction is diagnosed, and we continue to use a left anterolateral thoracotomy as the preferred approach for most patients.

Adolescent↗

PubMed1985

Mitral regurgitation due to ruptured chordae tendineae. Early and late results of valve repair.

From 1958 through 1980, 131 patients had repair of ruptured chordae tendineae of the mitral valve; 62% were men. Ages ranged from 5 to 70 years (median 57). Chordae to the anterior mitral leaflet were ruptured in 44 patients (34%), to the posterior mitral leaflet in 85 (65%), and to both leaflets in two patients (1%). The mitral valve was repaired by leaflet plication without resection in 116 patients, plication after wedge resection of the unsupported leaflet in six, Ivalon sponge buttress of the posterior leaflet in three, resuspension of chordae in two, and annuloplasty alone in the remaining four. Mitral valve annuloplasty was performed in addition to leaflet repair in 115 patients (88%). Operative (less than 30 days) mortality was 6.1%. Survival rate of patients dismissed from the hospital was 92% at 5 years and 73% at 10 years. There were no differences in late survival or risk of reoperation for recurrent or residual mitral insufficiency between patients with ruptured chordae to the anterior leaflet and those with ruptured chordae to the posterior leaflet. Survival was significantly better for the group with repair than it was for a group that underwent mitral valve replacement for ruptured chordae during this same time interval (5 year survival rate, 92% versus 72%, p less than 0.003). The incidence of thromboembolism after repair was 1.8 episodes/100 patient-years compared with 8.0 episodes/100 patient-years after replacement. Our data indicate that valvuloplasty is the procedure of choice for most patients with mitral regurgitation owing to ruptured chordae tendineae, including selected patients with ruptured chordae to the anterior leaflet.

Adolescent↗

PubMed1985

Update on infections involving permanent pacemakers. Characterization and management.

From January, 1974, to December, 1983, 75 patients with infections related to permanent pacemakers were successfully treated. Demographic characterization, mode of presentation, types of infecting organisms, potential predisposing factors, significance of a retained infected pacemaker lead, and various medical and surgical treatment methods were analyzed. Likely infecting organisms depended on the mode of presentation and the time of the infection. Dermatologic diseases accounted for a significant number of secondary infections. Removal of the entire infected pacing system was required for eradication of infection in 74 of 75 patients. In 31 patients, the infected system was removed at the same time that the new system was implanted. In 26 patients, a two-stage procedure was used that included a period of temporary pacing between explantation of the old system and implantation of the new. No difference in complications or incidence of reinfection was found between these two groups. Infections occurring within 2 weeks after operation accounted for 15% of the cases. In these patients, Staphylococcus aureus was the most common organism. In patients with later infections, Staphylococcus epidermidis was the most common.

Adult↗

PubMed1985

Surgical management of effusive pericardial disease. Influence of extent of pericardial resection on clinical course.

Surgical drainage for effusive pericardial disease is usually accompanied by pericardial resection to obtain tissue for analysis and to lessen the chance of recurrent effusion or late constriction. The purpose of this study was to determine the relationship between the extent of resection and the development of late complications. From 1960 through 1983, 145 patients with pure pericardial effusive disease underwent operative drainage. The effusions were malignant in 72 patients (49.7%) and benign in 73 (50.3%). The patients were divided into three groups according to the extent of resection: complete in 72 patients (49.7%), partial in 36 (24.8%), and window in 37 (25.5%). The 30 day mortality was 19.4% for patients with malignant effusions and 5.5% for those with benign effusions (p less than 0.05). All survivors had immediate improvement in symptoms. The actuarial 1 year survival rate was 23.4% (mean 4.2 months) for patients with malignant disease and 85.6% for patients with idiopathic effusions (p less than 0.001). Survival was not influenced by the extent of resection. Fifteen patients (10.3%) had late constriction or recurrent effusion. Six of these required reoperation, all after having had a window procedure. Actuarial probability of reoperation or late complication was greater with window procedures than other resections, both for all patients (p = 0.0001) and for those with benign disease (p = 0.0001). Transthoracic complete pericardiectomy is the procedure of choice for effusive pericardial disease. Subxiphoid drainage has immediate advantages for selected patients but has a statistically greater chance of late complications.

Adolescent↗

PubMed1985

Concomitant cardiac and pulmonary operations.

From 1965 through 1983, 43 patients underwent concomitant cardiac and pulmonary procedures at our institution. Most patients presented with cardiac symptoms and were incidentally found to have a roentgenographically indeterminate lung nodule. The pulmonary diagnosis of 38 patients was unknown preoperatively, and nine of these had a malignant lesion. All 43 cardiac procedures necessitated extracorporeal circulation. Thirty-one patients had benign pulmonary disease, 10 had bronchogenic carcinoma, and two had metastatic carcinoma. Concomitant pulmonary procedures were performed via median sternotomy and included single wedge resections in 32 patients, lobectomy in seven, multiple wedge resections in three, and pneumonectomy in one. Most resections were performed either before or after institution of bypass, without systemic anticoagulation. Of the two operative deaths (4.6%), one was related to intraparenchymal pulmonary hemorrhage after multiple wedge resections during anticoagulation. Thus, pulmonary resections performed during anticoagulation may be associated with increased risk and probably should be avoided. The second death was cardiac in origin and not related to pulmonary resection. The remaining patients recovered uneventfully. Definitive correction of both cardiac and pulmonary disease can be performed at one operation via a single incision with safety and benefit to the carefully selected patient.

Adolescent↗