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Biomedical subjects

W M Daggett

Publications and source records attributed to W M Daggett.

At least 109 records · Page 6Linked to original sources
PubMed1979

Effects of coronary bypass grafting on resting left ventricular contraction in patients studied 1 to 2 years after operation.

Left ventricular contraction was evaluated with angiography in 51 patients 1 to 2 years after coronary arterial bypass surgery. The left ventricle was classified into five segments, and segmental ventricular wall motion was analyzed with subjective and objective methods. With subjective analysis, 25 percent of asynergic segments showed improvement, 72 percent no change and 3 percent deterioration in contraction. There was a 5 percent incidence rate of new wall motion abnormalities in segments that were judged normal from the preoperative ventriculogram. Objective analysis revealed significant improvement in contraction of asynergic segments in each of the five left ventricular segments analyzed. Thus, 1 to 2 years after coronary bypass surgery, there was a significant reduction in left ventricular segmental wall motion abnormalities, and the incidence of deterioration in contraction was small.

Coronary Artery Bypass↗
PubMed1979

Mitral valve replacement: a nine-year follow-up of risks and survivals.

Experience with mitral valve replacement over a nine-year period is reviewed. Hospital mortality was 8.9%, with an additional late mortality of 18.5% during a mean follow-up period of 4.34 years. Study of the factors influencing the results of valve replacement revealed a direct correlation between long-term survival and New York Heart Association (NYHA) Functional Class, as judged preoperatively, as well as left ventricular end-diastolic pressure, cardiac index, type of valve lesion, and presence of associated coronary artery disease. Hospital mortality was 32% (p less than 0.01) for those patients in NYHA Functional Class IV before operation, compared with 3% for Class III patients. Untreated concomitant coronary artery disease was associated with a significantly higher perioperative mortality of 28% (p = 0.002) compared with an 8% mortality in patients with coronary artery disease treated by vein bypass at the time of mitral valve replacement. Patients with normal coronary arteries documented angiographically before operation had a 1% hospital mortality. Seventy-two percent of all patients are still alive at a maximum follow-up of nine years. Eighty-three percent of those survivors who were in Functional Class III or IV before operation are now considered to be in Class I or II. We conclude that patients should undergo mitral valve replacement before the development of the advanced functional stage of valve disease. In addition, coronary arteriograms should be performed on all patients who are more than 40 years old at the time of cardiac catheterization, and revascularization considered at the time of mitral valve replacement for those patients with significant coronary disease.

Adolescent↗
PubMed1979

Survival following mitral valve replacement for mitral regurgitation due to coronary artery disease.

Forty-six patients who underwent mitral valve replacement for mitral regurgitation due to coronary artery disease during 1970-1975 were identified. Forty patients underwent aortocoronary bypass procedures at the same operation. The survival rate at the fourth postoperative year was 73% in the 22 patients in whom the preoperative left ventricular ejection fraction exceeded 0.35, 38% in the 16 patients in whom the preoperative left ventricular ejection fraction was 35% or less, and 25% in the eight patients in whom aneurysmectomy was performed at the time of mitral valve replacement (p less than 0.05 for the former group compared to the latter two groups). Heart failure, present preoperatively in 41 patients, was improved in most of the long-term survivors. Neither the angiographic extent of coronary artery disease nor whether mitral valve replacement was performed in the acute (within 2 months in 13 patients) or chronic phase of myocardial infarction were distinctly correlated with survival.

Aged↗
PubMed1979

Safe early revascularization for continuing ischemia after acute myocardial infarction.

Early revascularization following myocardial infarction (MI) is reported to have a high risk of extension of and hemorrhage into infarction with resulting high mortality and morbidity. To evaluate this issue, 80 post-MI patients (aged 32-74 years) with unstable angina pectoris resistant to maximal medical therapy were reviewed. All patients underwent early uncomplicated angiography and subsequent revascularization; 55 (69%) were less than 10 days post-MI, and 25 (31%) were 10-30 days post-MI. Intraaortic balloon pumping was required in 72% for relief of intractable angina or hemodynamic instability. Of the 80 patients, 19% had single vessel disease (VD), 31% double VD, and 50% triple VD. The mortality rate from coronary bypass surgery was 7/80 (8.8%), with four cardiac and three noncardiac deaths. Two patients suffered a perioperative MI (2.5%). At a mean follow-up period of 33 months, there had been only one late death and one recurrent nonfatal MI; 96% of the patients had no significant angina. In patients with continuing ischemia immediately after MI, myocardial revascularization can be safely performed without further injury to the myocardium, and with excellent long-term results.

Adult↗
PubMed1978

Lymphatic vessels of the mammalian heart.

An in situ heart lung preparation was developed to label lymphatics of the actively beating dog heart with subsequent fixation by vascular perfusion. Immediately after interstitial injections of trypan blue and colloidal carbon, a rich plexus of lymphatic vessels was visualized in the epicardium of the actively beating heart. With this method of fixation, tissue preservation is generally excellent and uniform throughout the heart. In thin sections examined with the electron microscope, lymphatic vessels are easily recognized by the content of plasma proteins which is preserved as an electron dense precipitate that is evenly dispersed throughout the lumen. An extensive plexus of thin walled lymphatic vessels is observed throughout the epicardial, myocardial and subendocardial regions. Numerous anchoring filaments are observed closely apposed to the abluminal endothelial surface which extend into the surrounding connective tissue. The distribution and ultrastructure of the cardiac lymphatic vessels are discussed in relation to their role in the removal of interstitial fluid from the heart.

Animals↗
PubMed1978

Ventricular performance and myocardial water content during hemodilution in dogs.

In dogs anesthetized with chloralose-urethan on right heart bypass, left ventricular (LV) performance was assessed at constant LV stroke work before and for up to 2.5 h after crystalloid hemodilution was established. Lowering the hematocrit from 43.3 +/- 1.3% to 13.6 +/- 1.7% (SE) did not significantly change LV end-diastolic pressure (LVEDP) initially. After 80 min LVEDP increased slightly by 1.7 +/- 0.6 cmH2O (P less than 0.05) at a stroke work of 17.3 +/- 2.3 g.m. The value of dP/dt did not change significantly throughout. When LV function curves were generated by increasing cardiac output, the stroke work attained at an LVEDP of 10 cmH2O decreased with hemodilution from 23.9 +/- 3.5 to 20.8 +/- 3.9 g.m (NS). LV wall water content increased with hemodilution, from which it could be calculated that there was an 18.6% increase in LV mass. Thus, despite an increase in LV external girth demonstrated by LV circumferential gauges, it is possible that increased wall thickness due to the water gain resulted in little change or an actual decrease in LV end-diastolic volume. Thus, profound hemodilution can be attained with only slight depression of LV performance.

Anemia↗
PubMed1978

The effect of ischemia on thallium-201 clearance from the myocardium.

To determine the effect of ischemia on myocardial clearance of thallium-201 (201Tl), we studied 12 dogs with ischemia produced after the injection of Tl. Tl was given I.V. 10 minutes before left anterior descending (LAD) coronary artery ligation. 85Sr-microspheres (MS) were administered 5 minutes later, and control biopsies were obtained from the myocardium. The LAD was tied and repeat biopsies obtained from the ischemic zone (IZ) and normal zone (NZ) 15 minures and 2 hours later. 46Sc-MS were given just before the final giopsy. Tl activity in the IZ was not significantly different from that in the NZ either before LAD occlusion or 15 minutes and 2 hours later. Tl clearance at the end of 2 hours was not significantly different (27 +/- 5% vs 28 +/- 5%, IZ vs NZ respectively) between the two zones. The half-time of Tl clearance from both the IZ and NZ was calculated at 4.5 hours (consistent with previously reported normal values). This occurred despite a decrease in regional myocardial blood flow to 24 +/- 6% of control (P less than 0.01) in the IZ and an increase to 47 +/- 14% of control (P less than 0.01) in the NZ during the study. We conclude that myocardial ischemia does not alter the normal rate of Tl clearance from the myocardium.

Animals↗
PubMed1978

Coronary, ventricular, and pulmonary abnormalities associated with rupture of the interventricular septum complicating myocardial infarction.

Left ventricular wall motion abnormalities, the extent and location of coronary artery stenoses, and the radiographic evidence of pulmonary venous hypertension were analyzed in a retrospective study of 40 patients who had surgically proven rupture of the interventricular septum after myocardial infarction. In 33 patients in whom chest films were available, interstitial or alveolar pulmonary edema was present in 78%, while left ventricular enlargement was present in 82%. Of 26 patients who had coronary angiography, complete occlusion of the right coronary artery, left anterior descending artery, or left circumflex artery was present in 92%, with few, if any, collateral vessels around the occlusion. The location of the rupture in the muscular septum was always in the region of akinesis or dyskinesis. Posterior defects were associated with posterobasal and diaphragmatic akinesis, and anterior defects with apical akinesis. Left ventricular aneurysms were adjacent to the septal rupture in 68%, and 74% had mitral regurgitation. The right ventricular diaphragmatic wall in posterior rupture was always akinetic, indicating right ventricular infarction. Thus ventricular septal defect after myocardial infarction (1) tends to occur with multiple coronary occlusions about which little collateral flow develops; (2) can accurately be localized anteriorly or posteriorly in the muscular septum by the location of the akinetic left ventricular wall segment; and (3) has an associated right ventricular infarct when rupture is posterior.

Adult↗
PubMed1978

Management of acute myocardial ischemia with intraaortic balloon pumping and coronary bypass surgery.

Ninety-three patients with unstable angina pectoris resistant to maximum medical therapy were treated with intraaortic balloon pumping (IABP), early angiography, and myocardial revascularization. Sixty patients had no recent infarction: 42 with typical angina (ST depression > 0.1 mV) and 18 with variant angina (ST elevation > 0.2 mV). Thirty-three patients were post infarction (< 10 days), 25 with typical angina and eight with variant angina. IABP interrupted ischemic attacks in 75/93 (81%) and reduced frequency and intensity of attacks in the remaining patients. Mortality from revascularization was 5/93 (5.4%) with two deaths in the preinfarction group (3.3%) and three deaths in the postinfarction group (9.1%). Incidence of perioperative myocardial infarction was 2.2%. With an average follow-up of 38 months there have been four late deaths (4.5%), three secondary to myocardial infarction, and only one other symptomatic infarction. After operation, 93% have no significant angina, and 70% are fully active. When IABP is used to control recurrent ischemia, patients with refractory angina pectoris can be safely revascularized and have a favorable long-term prognosis.

Adult↗
PubMed1978

Clinical experience with intraaortic balloon pump support in 728 patients.

From November, 1968, through December, 1976, intraaortic balloon pump (IABP) circulatory support was used 747 times in 728 patients. Overall in-hospital survival was 413/747 (56.9%). Survival with IABP since 1974 has been 65% (286/440) compared to 24% (18/75) in 1968-1971 (P < 0.001). Two practical changes have been associated with this improvement: 1) broadened indications for, and earlier insertion of, IABP; and 2) more aggressive surgical treatment of the primary cardiac lesion. Cardiogenic shock or chronic ischemic ventricular failure accounted for 78.7% (59/75) of IABP in 1968-1971; during 1974-1976 only 26.4% (116/440) of IABP-supported patients were in these categories (P < 0.001). Since 1974, 58.2% (153/263) of IABP patients had an operative procedure following IABP insertion compared to 37.7% (23/611 prior to 1971 (P < 0.01). The major complication rate has remained unchanged at 8.5%. IABP-related mortality rate was 0.8% (6/728). Earlier, more liberal, use of IABP hemodynamic support has led to increased survival in a large number of patients with complications of acute myocardial ischemia. The low mortality associated with its use vindicates earlier institution of IABP support in cardiogenic shock.

Equipment Failure↗