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Biomedical subjects

M J Buckley

Publications and source records attributed to M J Buckley.

At least 145 records · Page 8Linked to original sources
PubMed1983

Coronary reocclusion after selective administration of streptokinase.

Intracoronary streptokinase was given to 40 patients with acute transmural myocardial infarction. In 34 of the patients (85%), it resulted in reflow or improved flow. Six patients showed no reflow and six reocclusion within 2 hours. No consistent explanation was found for this resistance to therapy. Five other patients developed reocclusion after 6 days to 11 months, when heparin or warfarin anticoagulation had been stopped. Percutaneous angioplasty at the time of streptokinase infusion was performed in seven, with six successes. Bypass surgery was performed after successful streptokinase administration in eight. Follow-up revealed recurrent ischemia in patients successfully treated with streptokinase alone, but not in patients with successful angioplasty or bypass surgery. Long-term coronary patency after thrombolysis may require careful anticoagulation or a procedure that modifies or bypasses the residual stenosis.

Angioplasty, Balloon↗
PubMed1983

Adrenocortical hormone levels during cardiopulmonary bypass with and without pulsatile flow.

To determine the effect of hypothermic pulsatile and nonpulsatile cardiopulmonary bypass (CPB) with hemodilution on adrenocortical function we measured plasma levels of adrenocorticotropic hormone (ACTH), cortisol, aldosterone, and renin in two groups of patients. Group I, comprising 11 patients had routine CPB (nonpulsatile), and Group II, comprising 12 patients, had pulsatile flow during CPB (pulsatile). Both groups demonstrated comparable increases in cortisol, ACTH, and aldosterone with operation. Levels for all three hormones appeared to decline during CPB and then rose again in the post-CPB period. There were no significant differences between groups. Plasma renin activity gradually declined in a comparable manner in both groups. In the post-CPB period, renin activity was slightly higher in the nonpulsatile group (1.7 +/- 0.5 versus 0.8 +/- 0.2 ng/ml/hr, p less than 0.05). Correction for the effect of hemodilution demonstrated no decrease in cortisol and a slight increase in ACTH in both groups during CPB. Significant increases occurred in both groups during CPB in urinary Na+ excretion rate and urinary Na+/K+ ratio, more so for the nonpulsatile group. There was no correlation between urinary Na+/K+ ratios and either plasma cortisol or aldosterone levels. Thus routine CPB demonstrates no evidence of adrenocortical hypofunction and the addition of pulsatile flow produces little improvement.

Adrenal Cortex Hormones↗
PubMed1983

Mechanical valves: a comparative analysis of the Starr-Edwards and Björk-Shiley prostheses.

Despite the requirement of anticoagulation, mechanical valve prostheses offer the advantage of proven durability. We have compared the long-term results of 467 aortic valve replacements and 342 mitral valve replacements using the Starr-Edwards prosthesis with 110 aortic valve replacements and 105 mitral valve replacements using the Björk-Shiley prosthesis from 1973 through 1977. Improvement in New York Heart Association (NYHA) class was noted in greater than 80% of patients in all four groups. Long-term survival with mean follow-up over 5 years was not significantly different between respective groups. The probability of thromboembolic complications, however, was significantly higher (p less than 0.05) with the Starr-Edwards prosthesis in both the aortic and mitral positions. The probability of valve failure, although low for all groups, was significantly higher (p less than 0.05) in the Björk-Shiley mitral group due to late thrombotic occlusion. Use of the Starr-Edwards and Björk-Shiley prostheses is associated with satisfactory functional improvement and similar long-term survival rate. However, the increased risk of valve failure due to late thrombotic occlusion of the Björk-Shiley prosthesis should be considered when choosing a mechanical mitral prosthesis.

Actuarial Analysis↗
PubMed1983

Vancomycin prophylaxis in cardiac operations: determination of an optimal dosage regimen.

Vancomycin is thought to be an acceptable alternative prophylactic antibiotic to the cephalosporins in penicillin allergic patients undergoing cardiopulmonary bypass. We studied the pharmacokinetics of vancomycin in 10 patients undergoing cardiopulmonary bypass. Our results suggest that the commonly used 500 mg dose (7 mg/kg) of vancomycin given preoperatively may provide serum concentrations during cardiopulmonary bypass which are not bactericidal for many S. epidermidis strains. Thus we believe that a higher initial dose, at least 15 mg/kg, should be given.

Cardiopulmonary Bypass↗
PubMed1982

Aberrant origin of the left coronary artery from the proximal right coronary artery: diagnostic features and pre- and postoperative course.

In this report, we present the pre and late postoperative course of a patient with severe angina secondary to aberrant origin or the left coronary artery from the proximal righ coronary artery (Fig. 1). We illustrate the noninvasive diagnosis and evaluation of this patient by two-dimensional ultrasound and stress thallium imaging, and the pre and late postoperative angiographic and thallium perfusion findings.

Angina Pectoris↗
PubMed1982

Improved results of surgical management of postinfarction ventricular septal rupture.

Fifty-five patients had surgical repair of postinfarction ventricular septal rupture in Massachusetts General Hospital from 1968 through 1981. In patients operated more than three weeks after infarction, hospital survival has been 93% (14/15). Before 1975 in patients operated less than three weeks after infarction, hospital survival was 41% (7/17). In this same era patents operated for septal rupture with cardiogenic shock present before operation had a hospital survival rate of only 27% (3/11). Before 1975 patients with cardiogenic shock were supported with intra-aortic balloon pumping (IABP) and vasopressors, and operation deferred pending hemodynamic stabilization. Before 1975 patients with anterior septal rupture had a hospital survival rate of 64% (9/14), while patients with posterior septal rupture had a hospital survival rate of only 38% (5/13). This difference in survival according to the location of septal rupture occurred despite comparable numbers of patients in each group requiring early operation, as well as incidence of cardiogenic shock. Since January 1, 1975 patients operated less than three weeks after infarction have had an overall hospital survival rate of 70% (16/23). Of the 10 most recent patients operated early, nine are survivors. In patients with anterior defects 85% (11/13) survived, while in patients with posterior defects 67% survived (10/15). In patients operated with cardiogenic shock present before operation, survival has been 67% (10/15). Changes in management leading to improved results include (1) immediate operation for patients with cardiogenic shock, (2) cold cardioplegic protection of the myocardium, and (3) prosthetic replacement of posterior left ventricular free wall defect, after infarctectomy and septal repair, in patients with posterior septal rupture.

Adult↗
PubMed1982

Isolated coronary artery bypass grafting in patients seventy years of age and older: early and late results.

Increasing longevity makes the consideration of coronary bypass common in elderly patients. Seventy-five patients 70 years of age or older undergoing coronary artery bypass grafting (CABG) for angina pectoris were compared to a control group of 75 patients under 70 years of age. The groups were matched for male:female ratio (46:29), previous infarction (28/75), unstable angina (27/75), and the requirement for preoperative intra-aortic balloon pumping (7/75). Patients under 70 years of age had an average preoperative New York Heart Association (NYHA) class of 3.0 +/- 0.6 (SEM) and an average left ventricular end-diastolic pressure of 15.5 +/- 0.8 mm Hg, compared to 3.3 +/- 0.6 and 12.9 +/- 1.1 mm Hg, respectively, for the older group. Average grafts per patient were 2.7 +/- 0.8 in the younger group and 2.8 +/- 0.1 in the older group. Overall operative mortality for patients under 70 was 4% (3/75) versus 12% (9/75) (p = 0.06) for patients 70 and older. The incidence of chronic stable angina was 2% (1/48) versus 6% (3/48) (p = 0.30). Perioperative infarctions occurred in 7% of those under 70 and 5% of those 70 or older (p = 0.54). Those under 70 averaged 13.8 +/- 0.6 postoperative hospital days versus 18.4 +/- 1.2 hospital days for the older group (p less than 0.05). Follow-up ranged from 2 to 94 months, averaging 22 months for patients under 70 and 24 months for those 70 or older. Late cardiac mortality rates were 4% (3/70) in the younger patients and 3% (2/66) in the older patients (p = 0.53). Current NYHA class was 1.3 +/- 0.7 for those under 70, with 9% reporting angina, and 1.4 +/- 0.7 for those who were 70 or older, with 6% reporting angina. CABG can be performed with acceptable risk in older patients and leads to encouraging symptomatic improvement and late survival.

Aged↗
PubMed1982

Thromboxane and prostacyclin changes during cardiopulmonary bypass with and without pulsatile flow.

Nonpulsatile cardiopulmonary bypass, in patients with coronary artery disease, produces a significant increase in thromboxane, a potent platelet aggregant and putative coronary vasoconstrictor. Pulsatile flow may decrease the incidence of perioperative infarction and the hormonal stress response to bypass. This study assessed the effect of pulsatile blood flow on plasma thromboxane and prostacyclin profiles during cardiopulmonary bypass by serial measurement of their stable metabolites, thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). Two groups of eight patients each were studied before, during, and after cardiopulmonary bypass. Eight patients had routine (nonpulsatile) bypass and eight had pulsatile flow. In the nonpulsatile group, the TxB2 concentration significantly increased during bypass (65 +/- 39 to 1,224 +/- 306 pg/ml, p less than 0.01) and rapidly returned to control. Prostacyclin also rose (53 +/- 20 to 613 +/- 132 pg/ml, p less than 0.01). In the pulsatile group, TxB2 rose during bypass (53 +/- 18 to 693 +/- 130 pg/ml, p less than 0.01), but peak concentration was significantly lower than in the nonpulsatile group (1,224 +/- 306 versus 693 +/- 130 pg/ml, p less than 0.05). Prostacyclin rose sharply during cardiopulmonary bypass in the pulsatile group (53 +/- 22 to 1,033 +/- 136 pg/ml, p less than 0.01) and was higher than in the nonpulsatile group (1,033 +/- 136 versus 325 +/- 33 pg/ml, p less than 0.01). There were no intragroup differences of plasma hemoglobin, hematocrit, or platelet count. These data demonstrate that pulsatile flow significantly alters prostacyclin and thromboxane profiles during cardiopulmonary bypass and favors production of the coronary vasodilator and platelet disaggregant prostacyclin. This may be an important factor in some of the clinical advantages previously reported with this modality.

6-Ketoprostaglandin F1 alpha↗
PubMed1982

Effect of the pH of cardioplegic solution on postarrest myocardial preservation.

The assumption that an alkaline cardioplegic solution is advantageous to the arrested heart is not supported by experimental evidence. Three groups of dogs were subjected to 2 hours of hypothermic arrest using a potassium cardioplegic solution of varying pH: group 1 (n = 8), pH 7.1; group 2 (n = 6), pH 7.4; and group 3 (n = 8), pH 7.7. Left ventricular (LV) function curves were obtained before arrest and after reperfusion, and the percent recovery of LV function was calculated. Coronary blood flow (CBF), oxygen and lactate use, and adenosine triphosphate and creatine phosphate were measured before and after arrest. Recovery of LV function was 83 +/- 4% (mean +/- SEM) in group 1 and 75 +/- 6% in group 2. LV function in group 3 was significantly depressed at 51 +/- 5% (p less than 0.01). Immediately after arrest, CBF and oxygen consumption were lowest in group 1 and highest in group 3 (p less than 0.01). CBF increased 23 +/- 9% in group 1, 110 +/- 29% in group 2 and 277 +/- 33% in group 3. Oxygen consumption was 2.2 +/- 0.4 vol/100 g/min in group 1, 3.63 +/- 0.5 vol/100 g/min in group 2 and 4.63 +/- 0.7 vol/100 g/min in group 3. All groups showed postarrest depression of adenosine triphosphate and creatine phosphate, but return of creatine phosphate to control was slowest in group 1 (p less than 0.01). These results indicate no advantage to an alkaline cardioplegic solution and suggest that an acidic cardioplegic solution, by inhibiting metabolism, may increase protection of the arrested heart.

Adenosine Triphosphate↗
PubMed1982

Acute oliguria after cardiopulmonary bypass: renal functional improvement with low-dose dopamine infusion.

Hemodynamic and renal function response to low-dose (100 and 200 micrograms/min) dopamine infusion was studied in 15 adult cardiac surgical patients who manifested combined oliguria and left ventricular dysfunction postoperatively. Patients were studied an average of 6.6 h after ICU admission, at normothermia and after 2 consecutive hourly urine output determinations of less than 0.5 ml/kg . h in the presence of a left atrial or pulmonary artery occlusion pressure over 12 mm Hg. Dopamine infusion at 100 micrograms/min produced improvement in creatinine, osmolar and free water clearances (70 +/- 10 to 115 +/- 13, 37 +/- 4 to 93 +/- 16 and --15 +/- 2 to --37 +/- 10 ml/min, respectively), and urinary sodium concentration (15 +/- 5 to 29 +/- 10 mEq/L). Urine flow improved overall from 22 +/- 2 to 54 +/- 9 ml/h; however, in 9 of 15 patients, flow was less than 0.5 ml/kg . h (33 +/- 5 to 50 +/- 6 ml/h). In each of these 9 patients, dopamine infusion at 20 micrograms/min further improved urine flow as well as measured renal function. Plasma renin activity measured in 9 of the 15 patients before and during the 100 micrograms/min dopamine infusion was decreased from 1.95 +/- 0.57 to 0.73 +/- 0.39 ng/ml . h. The hemodynamic effect of both dopamine doses was increased cardiac output coupled with decreased systemic (SVRI) and pulmonary vascular resistance index (PVRI). In these 15 patients, low-dose dopamine infusion produced significant improvement in renal function, with resolution of oliguria in every case, and with no deleterious hemodynamic effect.

Adult↗
PubMed1982

Should we pulse?

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Cardiopulmonary Bypass↗
PubMed1981

Spectrum of congestive heart failure late after aortic valve or mitral replacement: differentiation of valvular versus myocardial cause by radionuclide ventriculogram-ejection fraction.

Heart failure (CHF) appearing late after aortic (AV) or mitral valve (MV) replacement (R) may be due to mechanical factors such as prosthetic or native dysfunction, or due to myocardial disease. We studied 41 patients who developed CHF late (6 weeks to 11 years) after AVR or MVR with gated blood pool scan (RNV) to analyze the spectrum of ejection fraction (EF) and its clinical correlates. Of the 17 patients who developed CHF after AVR, 10 had RNV EF greater than 0.5 (all of whom had severe valve or prosthetic dysfunction as the primary cause of CHF) and seven had EF less than 0.5 (five with severe myocardial disease and two with prosthetic dysfunction). Of the 24 with CHF after MVR, 13 had RNV EF greater than 0.5. In contrast to post-AVR patients, only 8 of the 13 patients had mechanical causes of CHF (seven prosthetic dysfunction and one constrictive pericarditis). Of the 11 patients after MVR with EF less than 0.5, nine had severe myocardial disease and two had prosthetic dysfunction. Thus (1) reduced EF in patients and CHF-after AVR or MVR suggests myocardial disease as the basis for CHF, and (2) normal EF implies a mechanical cause of CHF after AVR but may be associated with either myocardial or mechanical factors after MVR.

Adult↗
PubMed1981

Prospective study of medical and urgent surgical therapy in randomizable patients with unstable angina pectoris: results of in-hospital and chronic mortality and morbidity.

At the Massachusetts General Hospital, all 190 patients who presented with the clinical and ECG criteria of the national Unstable Angina Pectoris Study (NUAPS) for unstable angina pectoris (UAP) were prospectively evaluated from their entrance between 1972 and 1976 (the entry period for NUAPS). Coronary angiography was performed in 166 patients. Of these, 83 patients (50%) were not eligible for randomization because of obstruction in the left main coronary artery (4%), inoperable diffuse coronary disease (11%), failure of initial medical therapy (20%), minimal coronary disease (13%), or other reasons (2%). The other 83 patients (50%) were eligible for randomization by NUAPS criteria; 39 received medical therapy and 44 underwent urgent coronary artery bypass surgery (CABG). The medical and surgical patients were comparable in terms of clinical characteristics and extent of anatomical disease. In-hospital (3% medical and 2% surgical) and late (5% medical and 5% surgical) mortality were similar over a mean follow-up period of 46 months. Myocardial infarction rate was statistically similar in-hospital (5% medical and 11% surgical) and during chronic evaluation (5% medical and 14% surgical). However, late severe angina (NYHA class III or IV) occurred in a significantly higher percentage of medical patients (28% medical versus 9% surgical; p less than 0.05) and nine medical patients (23%) required late elective CABG for relief of persistent angina. This experience is comparable to NUAPS, and supports the conclusion that acute management of unstable angina pectoris may begin with intensive medical treatment followed later by more elective CABG for those patients with persistent angina despite medical therapy.

Angina Pectoris↗