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Biomedical subjects

D S Beanlands

Publications and source records attributed to D S Beanlands.

At least 37 records · Page 2Linked to original sources
PubMed1989

Late reassessment of percutaneous transluminal coronary angioplasty results: clinical, exercise and angiographic follow-up.

One hundred and forty-five patients underwent percutaneous transluminal coronary angioplasty (PTCA) in the authors' hospital between 1981 and 1983. Four have since died and all but one of the remainder were accounted for at follow-up 41 +/- 12 months later. Recurrence of angina was present in 28% of patients having successful PTCA versus 33% of patients with surgery for failed PTCA. Use of antianginal drugs and return to work was similar in the two groups. Mean treadmill time, peak heart rate, incidence of treadmill angina and exercise thallium-201 defects were not different in the two groups. Late follow-up coronary angiography in 60 patients who had successful PTCA showed a significant decrease in mean stenosis of the dilated segment from 31 to 23%. Of 25 patients who had late angiography after failed PTCA, three had satisfactory patency of the dilated segment. New significant coronary stenosis was seen in only 17% of patients not having coronary bypass surgery.

Angioplasty, Balloon, Coronary↗
PubMed1988

Comparison of ioxaglate with diatrizoate in angiography of the internal mammary artery.

To compare ioxaglate with the traditional agent diatrizoate, 44 patients scheduled to undergo coronary angiography that included internal mammary artery (IMA) visualization were entered into a randomized double blind-parallel design protocol. Complete data were collected on 32 out of 44. Four patients were withdrawn because of angiographically normal coronary arteries; seven, because of unsuccessful IMA cannulation; and one, because of an anaphylaxis-like reaction to ioxaglate. No other serious adverse effects were seen with either agent. The major endpoints were patient and physician assessments of discomfort, rated independently on a 4-point scale. Ioxaglate caused significantly less discomfort (n = 17, median rating of "mild discomfort") than did diatrizoate (n = 15, median rating of "severe discomfort"; P less than 0.01); this effect was independent of patient sex, the number of injections, and the volume of dye injected. Radiographic quality was good with both agents. We conclude that ioxaglate is much better tolerated than diatrizoate during angiography of the IMA.

Diatrizoate↗
PubMed1988

Urgent surgical reperfusion in acute evolving myocardial infarction. A randomized controlled study.

To assess the benefit of immediate surgical reperfusion over conventional medical treatment during the first acute evolving transmural myocardial infarction, 68 patients presenting within 4 hours of onset of chest pain were randomized into a medical group and a surgical group. Both groups were comparable for age, sex, coronary risk factors, location of infarct, and coronary anatomy. Radionuclide global ejection fraction at 48 hours after admission was 45 +/- 15% for the medical group versus 50 +/- 15% for the surgical group; at 3 months, ejection fraction values were 51 +/- 13% and 51 +/- 13%, respectively (p = NS). The average radionuclide wall-motion scores (normal, 3) at 3 months were 2 +/- 0.6 for the medical group and 2 +/- 0.7 for the surgical group. There were three (8.8%) early and four (11.7%) late deaths in the medical group and only one (2.9%) early death in the surgical group. Urgent surgical reperfusion in acute evolving myocardial infarction is a safe and effective procedure that appears to reduce early and late mortality but does not appear to improve left ventricular function.

Clinical Trials as Topic↗
PubMed1988

Perioperative variability of binding of lidocaine, quinidine, and propranolol after cardiac operations.

This study examined the effect of changes in plasma concentrations of total protein, albumin, alpha 1-acid glycoprotein, and free fatty acids occurring after heart operations on the protein binding of chemically basic drugs. Plasma protein and free fatty acid concentrations were measured simultaneously with in vitro determinations of the protein binding of lidocaine, quinidine, and propranolol: immediately before operation, immediately on weaning from cardiopulmonary bypass, on arrival in the recovery room, and 12, 24, 72, and 120 hours postoperatively. Initial decreases in the concentrations of all proteins were followed by a rise in alpha 1-acid glycoprotein to 254% of baseline at 72 to 120 hours. The free fractions of drug were initially increased to 168% of baseline for lidocaine, 206% for quinidine, and 200% for propranolol and fell progressively with time, reaching sustained troughs of 65% for lidocaine, 50% for quinidine, and 57% for propranolol at 72 to 120 hours. Regression analysis indicated a major influence of changing alpha 1-acid glycoprotein concentrations on free fractions of all three drugs, with a smaller effect of albumin that reached statistical significance only for lidocaine. There were no significant perioperative changes in plasma concentrations of free fatty acids when the in vitro effects of heparin were controlled. In conclusion, sequential changes in plasma protein concentrations after cardiac operations predictably alter the protein binding of lidocaine, quinidine, and propranolol and should be considered when interpreting total plasma drug concentrations.

Blood Proteins↗
PubMed1987

Intracoronary streptokinase: effects on reperfusion hemorrhage and regional myocardial blood flow in the anesthetized dog.

The effects of intracoronary streptokinase on reperfusion-induced myocardial hemorrhage and regional myocardial blood flow were examined. Anesthetized dogs were reperfused for 2 h following 4 h of circumflex coronary occlusion. Fourteen animals received 250,000 IU intracoronary streptokinase during the reperfusion period and 13 received an equivalent volume of normal saline. Radioactive microspheres were injected 15 min before, 10 min after, and 2 h after reperfusion. Hemorrhage was quantitated by a scoring system and by measuring the hemoglobin content of the infarcted posterior papillary muscle as well as the total infarct. Infarct size was quantitated using nitroblue tetrazolium to demarcate the necrotic myocardium. Postmortem examination revealed that gross myocardial hemorrhage occurred within the borders of the infarct in both groups. The hemoglobin was 6.9 mg/g in normal myocardium. There was no statistical difference between the saline- and streptokinase-treated animals as regards posterior papillary muscle hemoglobin (12.8 vs. 15.8 mg/g) or total infarct hemoglobin (10.5 vs. 11.2 mg/g). Hemorrhagic scores in the two groups were also not statistically different. Reperfusion flows measured 10 min after reperfusion averaged 0.69 ml/min/g for the saline-treated animals and 0.55 ml/min/g for the streptokinase-treated animals (p greater than 0.05). Reperfusion flows measured 2 h after reperfusion were also not statistically different (0.49 vs. 0.44 ml/min/g). In this experimental preparation, streptokinase does not augment reperfusion hemorrhage or adversely affect reflow measured in the early hours following reperfusion.

Anesthesia↗
PubMed1987

Do symptoms reflect a change in left ventricular function after aortocoronary bypass grafting in patients with depressed left ventricular function?

Seventy-nine patients with moderate to severe left ventricular dysfunction who underwent aortocoronary bypass grafting between 1971 and 1977 had follow-up heart catheterization at a mean interval of 3 years. Thirty-three patients (42%) had angiographic improvement in left ventricular function at follow-up and 18 (25%) had a decrease in left ventricular end-diastolic pressure. Fifty-eight patients (73%) had improvement in angina of at least one New York Heart Association class at follow-up. There was no correlation between late improvement in left ventricular function and improvement in angina. Improvement in left ventricular function did not correlate with preoperative indices of severity of coronary disease or with indices of completeness of surgical repair.

Adult↗
PubMed1984

Complications of cardiac catheterization: one centre's experience.

Data on complication rates in a cardiac catheterization laboratory were prospectively gathered over a 6-year period. During this time 7960 catheterizations were performed. Death occurred in seven (0.1%) of the cases. The difference between the mortality rates for procedures performed with and without systemically administered heparin (0.04% and 0.2% respectively) was barely statistically significant (p less than 0.05). A significant complication occurred in 1.5% of the cases; however, most did not have long-term sequelae. No significant change in the annual rate of such complications was seen during the study period. Such a tabulation permits audit of quality of care, points out changing trends in morbidity and offers meaningful information on the safety of cardiac catheterization to referring physicians and their patients.

Arrhythmias, Cardiac↗
PubMed1984

Comparison of clinical and treadmill variables for the prediction of outcome after myocardial infarction.

To assess the relative prognostic merits of 15 clinical and 10 predischarge exercise test variables, 226 patients who had sustained an acute myocardial infarction were studied. A submaximal treadmill test was performed on 205 patients to a mean work load of 5.7 +/- 2.9 METS. Testing was performed an average of 11.7 (range 6 to 33) days after myocardial infarction. During the first year of observation, major cardiac events were noted in 33 patients (16%), unstable angina in 7 (3.4%), recurrent myocardial infarction in 14 (6.8%) and death in 12 patients (5.9%). Cardiac mortality correlated with mean peak serum creatine kinase (CK) (p less than 0.05), history of previous myocardial infarction (p less than 0.01) and ST segment depression at rest (p less than 0.01). The only exercise variable that correlated with cardiac mortality was poor exercise endurance (p less than 0.05). Multivariate risk stratification of clinical and treadmill variables from these 205 patients using linear discriminant analysis produced a function that correctly classified 95% of those who were event-free and 80% of those who died. The first four discriminant variables that contributed independent information for the prediction of cardiac mortality were: 1) ST segment depression at rest; 2) CK greater than 1,280 IU/liter; 3) exercise duration less than 3 minutes; and 4) a history of previous myocardial infarction. ST segment depression on the predischarge treadmill test did not predict any event, nor did it improve the predictive accuracy of the clinical variables. It is concluded that a history of previous myocardial infarction and ST segment depression on the rest electrocardiogram indicate a poor prognosis after acute myocardial infarction. Poor endurance is the only exercise variable that suggests a future cardiac event. Prognosis after acute myocardial infarction is more accurately predicted by these clinical data than by variables derived from the predischarge treadmill test.

Adult↗
PubMed1983

The time course and characterization of myocardial hemorrhage after coronary reperfusion in the anesthetized dog.

We quantitated hemorrhage associated with reperfusion after varying periods of myocardial ischemia and examined the flow characteristics that accompany reperfusion hemorrhage. Anesthetized dogs were reperfused after 2, 6 or 24 hours of circumflex occlusion. A control group underwent coronary occlusion without reperfusion. Radioactive microspheres were injected before and 5 minutes and 24 hours after reperfusion. The papillary muscles were analyzed for hemoglobin content, flow during myocardial ischemia and flow early and 24 hours after reperfusion. Myocardial creatine kinase activity was assayed to determine the severity of myocardial necrosis in the papillary muscles. Hemorrhage into the posterior papillary muscle was dependent upon the duration of coronary artery occlusion. Posterior papillary hemoglobin averaged 14 mg/g in the 2-hour group, 28 mg/g in the 6-hour group and 36 mg/g in the group reperfused 24 hours after occlusion, compared with 8.7 mg/g in the control group. Myocardial hemorrhage was associated with severe depression in myocardial CK and marked depression in flow to the ischemic area (i.e., collateral flow) during the occlusion. Early reflow averaged 112 ml/min/100 g in the 2-hour group, 61 ml/min/100 g in the 6-hour group and only 5.8 ml/min/100 g in the 24-hour group. Therefore, myocardial hemorrhage induced by reperfusion of the acutely ischemic myocardium is associated with severe ischemia during occlusion and severe myocardial necrosis, but does not depend upon the magnitude of early reflow. Myocardial hemorrhage may occur even though initial reflow values are markedly decreased.

Animals↗
PubMed1983

Influence of protamine on heparin-induced increases of lidocaine free fraction.

It has been suggested that heparin-induced increases in drug free fraction are largely artifactual as a result of continued in vitro activity of lipoprotein lipases after blood samples collection. The influence of different concentrations of protamine (1.0, 2.5, 5.0 and 10.0 mg/ml), an inhibitor of lipoprotein lipases, on lidocaine free fraction was studied before (control) and 10 min after heparinization (3000 IU) in 7 cardiac catheterized patients. Heparin increased the mean free fraction of lidocaine by 85% (p less than 0.001) and was associated with more than 2-fold increases in free fatty acids (FFAs). The presence of protamine at 2.5, 5.0 and 10.0 mg/ml diminished both the heparin-induced elevation of lidocaine free fraction (p less than 0.001) and FFAs (p less than 0.001). At a protamine concentration of 10.0 mg/ml, the FFAs remained higher than control value (p less than 0.05) while the free fraction was not different from control preheparin value. There were significant relationships (p less than 0.01) between log protamine concentration and the changes in both free fraction (r2 = 0.906) and FFAs (r2 = 0.931). The inhibitor also reduced (p less than 0.01) the lidocaine free fraction in control samples but these changes were not correlated with changes of FFAs. These results indicate that it is impossible, at this point, to abolish the artifactual effect of heparin without altering protein binding of lidocaine.

Adult↗
PubMed1979

Fate of the graft and native vessel following endarterectomy of the left anterior descending coronary artery.

In 16 patients who underwent endarterectomy of the left anterior descending (LAD) coronary artery combined with saphenous vein bypass grafting between Aug. 1, 1976 and July 31, 1978, the results of preoperative and postoperative angiography were comparable. Most patients had obstruction or severe stenosis of the proximal LAD coronary artery together with a poor runoff as demonstrated angiographically. Eighteen vein grafts were placed in the LAD artery and 15 (83%) were satisfactorily patent. Six of 18 grafted arterial segments became occluded distal to the site of graft insertion, but in most cases there was sufficient proximal runoff to maintain graft patency. In this study intraoperative measurements of graft flow were predictive of graft or distal vessel patency, or both. Careful postoperative assessment of the results of this technique seems warranted.

Adult↗