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Biomedical subjects

E L Alderman

Publications and source records attributed to E L Alderman.

At least 91 records · Page 5Linked to original sources
PubMed1987

Effect of acute human cardiac allograft rejection on left ventricular systolic torsion and diastolic recoil measured by intramyocardial markers.

Left ventricular systolic torsion and diastolic recoil were quantified in 12 human cardiac transplant recipients with surgically implanted intramyocardial markers with the use of computer-aided analysis of biplane cineradiographic images. Measurements were performed between 6 and 16 weeks after surgery and related to the presence or absence of rejection as determined by cardiac biopsy. Torsional deformation, defined as twisting about the left ventricular long axis of the apical region with respect to the base, was characterized in terms of the rate and amplitude of systolic torsion and the rate of diastolic recoil by means of an internal reference system. Comparison of measurements before, during, and after recovery from 14 rejection episodes allowed assessment of the effects of acute reversible cardiomyopathy on left ventricular torsion and recoil. Compared with prerejection values, the amplitude of torsional deformation in the maximally deforming segment (theta max) decreased by 25% from 21.1 +/- 15.2 to 16.0 +/- 5.7 degrees (p less than .005) during acute rejection with myocyte necrosis; this was associated with significant (p less than .05) decreases in the peak systolic torsion rate (+d theta/dtmax), whereas the peak diastolic recoil rate (-d theta/dtmax) was unchanged. This suggests that the stiffness of elastic components of the myocardium may have increased, maintaining the rate of diastolic recoil when these elements are stretched less. With successful treatment of rejection episodes, the torsional deformation characteristics normalized. Heart rate, mean arterial pressure, left ventricular end-diastolic volume, stroke volume, ejection fraction, and peak left ventricular filling rate were unchanged with rejection episodes, whereas left ventricular end-systolic volume increased (p less than .05) during acute rejection and returned to normal with resolution of the rejection process. These data suggest that left ventricular torsional deformation amplitude and rate are sensitive to episodes of subclinical left ventricular dysfunction and that such intramyocardial marker techniques may provide new insights regarding the elastic properties of the ventricular myocardium and their impact on left ventricular mechanics.

Acute Disease↗
PubMed1987

Clinical and laboratory correlates of accelerated coronary artery disease in the cardiac transplant patient.

Accelerated coronary disease in the cardiac allograft (TxCAD) is a major complication affecting long-term survival of heart transplant patients. Since the transplanted heart remains denervated, the first sign of TxCAD may be silent myocardial infarction or sudden death. The prevalence of this disease has been unaltered since the advent of cyclosporine immunosuppression. Serial annual coronary arteriograms in 132 patients undergoing transplantation after 1979 at Stanford revealed 44 patients who developed TxCAD (33%). Multiple variables, including patient lipid profile, extent of donor and recipient tissue match, age of recipient and donor, number of rejection episodes, prednisone dose, and fasting blood sugar were examined in relation to occurrence of TxCAD. Donor age was greater among the 44 patients developing TxCAD that in the 88 patients who did not develop coronary artery disease (23.5 +/- 5.8 vs 21.3 +/- 5.7 years, p less than .05). The fasting plasma triglyceride level 1 year after transplantation was 236.0 +/- 246.3 mg% in the patients with TxCAD vs 170.1 +/- 108.2 mg% in those without TxCAD (p less than .05). No other indexes, including number of rejection episodes during first posttransplant year, number of HL-A mismatches, level of maintenance steroids, fasting blood sugar, and cholesterol subfractions identified patients who developed TxCAD. We conclude that TxCAD has limited correlation with the clinical and laboratory factors analyzed. Higher donor age and elevated plasma triglycerides may be significant predisposing factors for the development of TxCAD.

Adult↗
PubMed1986

Diltiazem and propranolol in combination: hemodynamic effects following acute intravenous administration.

Diltiazem and propranolol are independently useful antianginal agents with common negative chronotropic, dromotropic, and inotropic properties. Concern over the safety of the concurrent use of these two drugs led to an investigation of their intravenous combination in 19 patients with suspected coronary artery disease. Hemodynamics were recorded in both a sinus and atrial paced rhythms at baseline and again following administration of a loading dose of diltiazem (0.25 mg/kg) followed by continuous infusion (0.002 mg/kg/min). Propranolol was then added by intravenous bolus (0.07 mg/kg) and continuous infusion (0.0012 mg/kg/min), with reassessment of hemodynamics once steady state was achieved. Patients were stratified by left ventricular ejection fraction (LVEF): group 1 (LVEF = 62% to 69%), group 2 (LVEF = 49% to 59%), and group 3 (LVEF = 20% to 47%). The combination of drugs resulted in a 15% drop in heart rate (p less than 0.01) and a 15% prolongation in the PR interval (p less than 0.01) for the group of 19 patients. Left ventricular end-diastolic pressure (LVEDP) was not significantly changed by diltiazem or its combination except in group 3. Cardiac output was lowered in all groups following diltiazem and propranolol (p less than 0.05). Untoward reactions included marked vasovagal reactions at the conclusion of the procedure in six patients. The combination of drugs resulted in profound sinus bradycardia with attendant 2:1 atrioventricular (AV) block in one patient. Diltiazem and propranolol were hemodynamically well tolerated in patients with preserved left ventricular function. Because of the additive negative dromotropic activities of these two drugs, ECG monitoring is warranted when they are acutely combined.

Adult↗
PubMed1986

Optimal detection of the progression of coronary artery disease: comparison of methods suitable for risk factor intervention trials.

To assess the best method of quantitating progression of coronary disease, we studied four measurements in 114 coronary segments from 35 medically treated patients from whom angiograms were obtained 5 years apart. Only stenoses of less than 70% that were visualized in nearly identical projections on both angiograms were evaluated. Vessel edges were measured by use of catheter calibration and an automated computer algorithm yielding two "absolute dimensions" (mean and minimum diameters) and two measurements (percent stenosis and atheroma area) that required a "normal reference" diameter. The coefficient of variation for repeated segment measurements was less for mean and minimum diameter than for percent stenosis and area of atheroma. The best measure of progression of coronary disease as determined by t test comparison of different methods was the change in mean diameter over time (6.7 +/- 14.1% decrease), whether calculated on a per coronary segment or per patient basis (p less than .001). Based on this measurement and its standard deviation of progression of coronary disease in this patient subset with relatively benign disease, it is estimated that 470 patients per group would be required for an interventional study to demonstrate a 33% reduction in disease progression (207 patients for 50% reduction) at a 95% confidence level and 90% power.

Cardiac Catheterization↗
PubMed1985

Independence of left ventricular pressure-volume ratio from preload in man early after coronary artery bypass graft surgery.

The response of the maximum value of the left ventricular pressure-volume ratio to preload augmentation by blood or plasma expanders was studied in 11 patients during the first 24 hr after coronary artery bypass graft surgery. Increasing the mean left atrial pressure from 10 to 15 and 20 mm Hg resulted in no change in the maximum pressure-volume ratio in the group as a whole. In certain individual patients, however, the maximum pressure-volume ratio changed with volume infusion, and these changes were accompanied by simultaneous changes in afterload. The observed changes in pressure-volume ratio were in the same direction as the changes in afterload (systolic pressure), suggesting a dependence of maximum pressure-volume ratio on afterload. These results show that the maximum pressure-volume ratio is independent of preload in the first 24 hr after coronary artery bypass graft surgery with the pericardium open; thus the maximum pressure-volume ratio is a useful index of postoperative left ventricular function when afterload is unchanged. However, because this ratio (a single-point assessment of the pressure-volume relationship) may not be a good estimate of Emax, we recommend a more complete determination of the locus of the "upper left corners" of the pressure-volume loops for measurement of Emax to provide a more accurate indicator of the myocardial contractile state.

Adult↗
PubMed1985

Effect of early postoperative volume loading on left ventricular systolic function (including left ventricular ejection fraction determined by myocardial marker) after myocardial revascularization.

The effects of early volume loading in terms of isovolumetric-phase and ejection-phase indexes of left ventricular systolic function were studied in 12 patients 5 hr after myocardial revascularization, with myocardial markers used to measure left ventricular volume directly and with simultaneous transmural left ventricular pressure measurements by micromanometers. Volume loading (increasing transmural left ventricular end-diastolic pressure from 11 +/- 4 to 15 +/- 5 mm Hg) induced a significant 14% increase in left ventricular end-diastolic volume index (LVEDVI), which was associated (as expected) with significant (p less than .005) augmentation of stroke work (+26%), left ventricular pressure-volume loop area (+35%), and stroke volume index (+22%) and with increments in left ventricular dP/dt and mean velocity of circumferential fiber shortening despite a simultaneous increase in left ventricular afterload. In contrast to previous radionuclide studies, however, left ventricular ejection fraction increased significantly (+9%) and the left ventricular end-systolic pressure-volume ratio did not fall. The relative change in ejection fraction was directly proportional to the increment in LVEDVI (r = .54, p = .03) and inversely related to the change in left ventricular end-systolic volume index (r = -.71, p = .0005). Patients who demonstrated a small or no increase in ejection fraction generally had a larger simultaneous increase in afterload, but one patient exhibited exhaustion of preload reserve. Ejection fraction, as an ejection-phase index of left ventricular performance, is highly dependent on afterload; therefore, interpretation of postoperative changes in ejection fraction must be undertaken only with strict caution.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1984

Randomized comparison of intravenous versus intracoronary streptokinase for myocardial infarction.

The efficacy of intravenous (i.v.) thrombolytic therapy has not been firmly established in comparison with the intracoronary (i.c.) route of administration. In a randomized trial of 28 patients who underwent angiography before and during i.v. and i.c. administration of streptokinase (STK), recanalization was achieved in 73% of patients who received the drug by the i.c. route, compared with 62% of patients who received the drug by the i.v. route (difference not significant). Reopening took 28 minutes for i.c. STK and 39 minutes for i.v. STK. Patients in whom recanalization was successful using either route of administration had shorter euglobulin lysis times and lower fibrinogen levels than did patients in whom it was not successful (p less than 0.05). Bleeding complications were closely correlated with heparinization after thrombolysis rather than with STK itself. These results in a limited patient series suggest that early administration of i.v. STK in the emergency department may yield recanalization rates similar to those for the i.c. route and may benefit myocardial preservation by restoring flow much earlier.

Aged↗
PubMed1984

Computerized quantitative analysis of left ventricular wall motion by two-dimensional echocardiography.

Quantitative detection of left ventricular segmental wall motion abnormalities by any modality depends on the reference system used because of the dynamic geometry of contraction and cardiac motion within the thorax. To assess the feasibility and accuracy of quantitative analysis of left ventricular wall motion by two-dimensional echocardiography, we studied 61 subjects with the use of 44 different reference methods in each of three echocardiographic views: the parasternal short-axis view at the levels of the mitral valve and of the papillary muscles and an apical four-chamber view. The three major groups of reference systems used were those with a fixed external reference, a floating reference correcting for translation, and systems correcting for both translation and rotation. In the first part of this study the end-diastolic and end-systolic outlines of 20 normal subjects were stored in a computer and composite data of these 20 subjects were plotted to obtain a 95% confidence interval for measured normal fractional change for each reference method. In the second part of the project an additional prospective group of 10 normal subjects and a group of 31 "abnormal" patients had their left ventricular wall motion analyzed by similar methods and the results were compared with all the confidence intervals. One reference method was selected for each two-dimensional echocardiographic view based on the highest sensitivity and specificity found by statistical analysis; a floating-reference system including translation was found to be optimal for the apical four-chamber and parasternal short-axis views at the level of the mitral valve and a fixed external reference system was optimal for the short-axis view at the papillary level. The percent fractional shortening of radial dimensions (radial methods) and the percent fractional change in area measurements (area methods) during the cardiac cycle were also calculated at 5, 10, 20, 30 and 45 degree intervals around the outline perimeter for each subject according to each of the 44 different methods. Area methods yielded the same specificity and sensitivity as radial dimension analysis methods at 5 to 45 degree intervals. Ten normal subjects underwent repeat echocardiography within 2 days of their first study to examine day-to-day variation. Average change in mean contraction from day to day was 7% to 9% for radial methods and 9% to 13% for area methods. In conclusion, we present a computerized system for unbiased selection of optimal methods of analysis of left ventricular wall motion by two-dimensional echocardiography.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Detrimental effect of perioperative myocardial infarction on late survival after coronary artery bypass. Report from the Coronary Artery Surgery Study--CASS.

The influence of perioperative myocardial infarction on late survival after coronary artery bypass grafting was reviewed in 9,777 patients who underwent operation between 1974 and 1979. Definite or probable perioperative myocardial infarction was diagnosed in 561 patients (5.7%). The incidence decreased from 6.6% in 1974 to 4.1% in 1979 (p less than 0.005). Actuarial survival, including hospital deaths, at 1, 3, and 5 years was significantly greater in patients without infarction than in patients with infarction (96%, 94%, and 90% versus 78%, 74%, and 69%; p less than 0.0001). The difference persisted among patients dismissed from the hospital. Reduction in late survival among patients with perioperative infarction was due to the poor outcome of those who had complications (5 year survival rates 40% overall and 73% for patients dismissed from the hospital). Multivariate analysis identified perioperative myocardial infarction as an important independent predictor of late survival after bypass grafting; it was surpassed only by left ventricular function (wall motion score), age, and number of associated medical diseases.

Coronary Artery Bypass↗
PubMed1984

Dobutamine and dopamine after cardiac surgery: greater augmentation of myocardial blood flow with dobutamine.

Left ventricular hemodynamics, dimensions and coronary sinus blood flows were measured simultaneously after infusions of dobutamine and dopamine. Ten patients were studied 6, 10 to 15, and 24 hr after cardiopulmonary bypass surgery. The dose of each drug was adjusted to increase cardiac output by 25%. Heart rate was held constant with atrial pacing. Dobutamine and dopamine increased peak left ventricular dP/dt from baseline values by 72% vs 58% during the early study, 77% vs 78% in the intermediate study, and 95% vs 79% in the late study (all NS, difference between drugs). Similarly, there were no significant differences in hemodynamic response or in cardiac dimensions after the two drugs in any period. Both drugs increased myocardial oxygen uptake during the intermediate and late studies (32% vs 33% and 34% vs 25%). With dobutamine this increase was matched by a similar increase in coronary blood flow; however, failure of the expected increase in coronary blood flow with dopamine suggested coronary constriction. Although dobutamine and dopamine have similar hemodynamic effects, dobutamine has the advantage of not limiting the increase in coronary blood flow associated with increased oxygen demand.

Catecholamines↗
PubMed1983

Preoperative invasive testing in mitral stenosis: indications based on assessment of diagnostic yield.

The role of preoperative invasive testing in mitral stenosis was assessed in 82 patients undergoing cardiac catheterization for isolated mitral stenosis. The patients were diagnosed by physical examination and echocardiography and were considered for surgical treatment primarily to relieve dyspnea. They had no precordial murmur attributable to an aortic valvular lesion and had no history of chest pain. The presence of mitral stenosis was confirmed at catheterization in all patients. All 38 patients in New York Heart Association functional class III and 8 of 9 patients in class IV had hemodynamic confirmation of mitral disease warranting operation. Although a mitral gradient was present in all 35 patients in class II, operation was not recommended in 9 (26%) of 35 with normal or mildly elevated pulmonary arterial wedge pressure. Invasive testing did not increase preoperative knowledge of aortic. tricuspid, or pulmonary valvular lesions which required surgical treatment. Coronary arteriography was performed in 44 patients (54%) and identified 4 patients with luminal narrowing (greater than 70% diameter reduction) affecting 1 or 2 arteries. These results suggest that preoperative invasive testing in patients with mitral stenosis is unnecessary when symptoms are moderate to severe and clinical evidence of aortic valvular or coronary artery disease is absent. However, preoperative cardiac catheterization is indicated in patients with mild symptoms to avoid unnecessary or premature mitral valve operations.

Adult↗
PubMed1983

Use of survival analysis to determine the clinical significance of new Q waves after coronary bypass surgery.

There are few data on the long-term effects of new Q waves on survival and morbidity after coronary bypass graft surgery (CABG). We followed 1340 patients who underwent CABG in 1978 at 10 hospitals participating in the Coronary Artery Surgery Study (CASS). The incidence of perioperative Q-wave infarction was 4.76% (range 0.0-10.3% by hospital). The rate of infarction was higher in patients who had an increased left ventricular end-diastolic pressure or cardiomegaly on the preoperative chest radiograph. Patients who received more grafts or who had longer cardiopulmonary bypass time were also at higher risk of infarction. In a stepwise discriminant analysis of 44 clinical, angiographic and surgical variables, cardiopulmonary bypass time, topical cardiac hypothermia and cardiomegaly entered the stepwise selection of variables. Long-term survival was adversely affected by the appearance of new postoperative Q waves. The hospital mortality was 9.7% in the 62 patients who had new postoperative Q waves and 1.0% in the 1278 patients who did not (p less than 0.001); the 3-year cumulative survival rates were 85% and 95%, respectively (p less than 0.001). In patients who survived to hospital discharge, the presence of new postoperative Q waves did not adversely affect 3-year survival (94% and 96%, respectively). The survival rates were worse in patients who had a history of infarction or who had impaired left ventricular function preoperatively. The number of readmissions to hospital after CABG among the patients who had a transmural perioperative infarction was similar to to that among patients who did not. We conclude that the appearance of new Q waves after CABG adversely affects survival. The major impact on mortality occurs before hospital discharge. Patients who are destined to have a perioperative infarct cannot be predicted from commonly measured preoperative and angiographic variables.

Adult↗
PubMed1983

Results of coronary artery surgery in patients with poor left ventricular function (CASS).

We identified 420 medically treated and 231 surgically treated patients (coronary graft plus myocardial surgery in 30%) who had severe left ventricular dysfunction manifest by an ejection fraction below 0.36 and markedly abnormal wall motion. Compared with medically treated patients, those treated surgically had more severe angina (56.7% vs 29.0% class III or IV; p less than .001), less heart failure as predominant symptom (11.1% vs 18.8%; p less than .003), more severe coronary disease (66.7% vs 50.2% three-vessel disease; p less than .001), a greater concentration of left main coronary artery lesions greater than 70% (12.6% vs 3.8%: p less than .001), and a greater estimated extent of jeopardized myocardium (p less than .001). Multivariate regression analysis of survival, which adjusts for the above covariates, showed that surgical treatment prolonged survival (p less than .05), although it ranked below severity of heart failure symptoms, age, ejection fraction, and left main stenosis greater than 70% in determining prognosis. Surgical benefit was most apparent for patients with ejection fractions below 0.26 who had a 43% 5 year survival with medical treatment vs 63% with surgery. Surgically treated patients experienced substantial symptomatic benefit compared with medically treated patients if their presenting symptoms were predominantly angina; however, there was no relief of symptoms caused primarily by heart failure. We conclude that patients with predominantly ischemic pain symptoms, despite poor left ventricular function, benefit from surgery; however, operative mortality in this high-risk subset must equal or better the 6.9% obtained in this study.

Actuarial Analysis↗
PubMed1983

Prognostic value of angiographic indices of coronary artery disease from the Coronary Artery Surgery Study (CASS).

The Coronary Artery Surgery Study, CASS, enrolled 24,959 patients between August 1975 and June 1979 who were studied angiographically for suspected coronary artery disease. This paper compares the prognostic value for survival without early elective surgery of eight different indices of the extent of coronary artery disease: the number of diseased vessels, two indices using the number of proximal arterial segments diseased, two empirically generated indices from the CASS data, and the published indices of Friesinger, Gensini, and the National Heart and Chest Hospital, London. All had considerable prognostic information. Typically 80% of the prognostic information in one index was also contained in another. Our analysis shows that good prediction from angiographic data results from a combination of left ventricular function and arteriographic extent of disease. Prognosis may reasonably be obtained from three simple indices: the number of vessels diseased, the number of proximal arterial segments diseased, and a left ventricular wall motion score. These three indices account for an estimated 84% of the prognostic information available. 6-yr survival varies between 93 and 16% depending upon the values of these three indices.

Angiography↗
PubMed1982

Anatomically flexible, computer-assisted reporting system for coronary angiography.

A computer-assisted method for reporting coronary arteriographic findings has been developed. A videographic display with a touch input system permits finger pointing to designate arterial segments, lesion locations, graft insertion points and collateral vessels. The coronary diagram is flexible to accommodate variations in dominance and in the size and length of the left coronary system branches. Lesion severity, type and length of lesions, distal vessel anatomy, collateral circulation and coronary bypass grafts (including Y or jump grafts) are displayed pictographically. A tabular summary and graphic output provide a completed coronary report eliminating the need for narrative dictation. An edit mode provides capability for teaching and review. The computer-assisted reporting method has the advantage of automatic data encoding in formats suitable for data base storage and subsequent retrieval.

Angiography↗
PubMed1982

Relation of P-S4 interval to left ventricular end-diastolic pressure.

Reports have suggested that the interval between P wave onset and the fourth heart sound (P-S4 interval) reflects changes in left ventricular myocardial stiffness. We made simultaneous measurements of the P-S4 or atrial electrogram to S4 (A-S4) interval and left ventricular pressure in 19 patients with coronary artery disease who were studied before and after atrial pacing. Thirteen patients developed angina accompanied by significant rises in their end-diastolic pressure and a consistent decrease in P-S4 or A-S4 interval; whereas the six patients who had atrial pacing without the development of angina had no change in end-diastolic pressure, P-S4, or A-S4 interval. The resting data showed in inverse correlation between left ventricular end-diastolic pressure and the P-S4 interval. In addition, the P-S4 interval let us discriminate between patients with normal and abnormal end-diastolic pressure (greater than 15 mmHg).

Adult↗