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Biomedical subjects

J R Kramer

Publications and source records attributed to J R Kramer.

At least 55 records · Page 3Linked to original sources
PubMed1986

Coronary artery disease in patients with aortic aneurysm: a classification of 302 coronary angiograms and results of surgical management.

In an attempt to reduce early and late mortality caused by myocardial infarction in patients with aortic aneurysms, coronary arteriography and, when indicated, myocardial revascularization were performed prior to elective aortic reconstruction in 302 patients with infrarenal (289) or thoracoabdominal (13) aortic aneurysms. Severe correctable coronary artery disease (CAD) was identified in 31% of the entire series, whereas severe inoperable CAD was seen in another 5%. Severe, correctable CAD was documented in 42% of patients suspected to have CAD by standard clinical criteria and in 19% of those in whom CAD was not suspected. The overall mortality for 89 cardiac and 227 infrarenal aortic surgical procedures was 4,4%. Fatal complications after infrarenal aneurysm resection occurred in only one (1.6%) of 61 patients who had had preliminary myocardial revascularization.

Aged↗
PubMed1986

Survival of non-surgical patients with mild angina or myocardial infarction without angina.

A group of 408 catheterised patients who had mild angina or myocardial infarction without angina was selected in conformity with the criteria for entry into a previously reported randomised trial. Medical treatment had been chosen initially by the cardiologist, referring physician, or the patient, although 27% had late operation. Five year survival rates were 91% and 72% for mild angina with high or low ejection fractions and 85% for those who had myocardial infarction without subsequent angina. Survival rates were 95%, 88%, and 80% for one, two, and three artery disease respectively. For patients who had ejection fractions of at least 0.50, five year survivals were 95%, 89%, and 83% for one, two, and three artery involvement respectively. Good left ventricular function, single artery disease, and a short history were favourable prognostic variables in multivariate analysis of patients who had angina pectoris. Statistical methods of dealing with patients who had late operation influenced calculated survival, especially for patients at relatively high risk. The lower survival rates for the whole group and most subsets compared with survival rates in the randomised trial may be of clinical importance.

Angina Pectoris↗
PubMed1985

Comparison of stress digital ventriculography, stress thallium scintigraphy, and digital fluoroscopy in the diagnosis of coronary artery disease in subjects without prior myocardial infarction.

Exercise thallium scintigraphy is often used for the diagnosis of coronary artery disease (CAD). Exercise digital subtraction ventriculography and digital subtraction fluoroscopy are new diagnostic procedures with roles that have not been determined. To compare the relative accuracies of the digital techniques with thallium scintigraphy, 97 consecutive patients without myocardial infarction underwent all 3 tests on the day before their scheduled coronary angiograms. Forty-two patients had CAD (more than 50% diameter narrowing of 1 major artery). A fixed or reversible perfusion defect defined an abnormal thallium test response and a segmental wall motion abnormality at rest or with exercise defined an abnormal digital ventriculographic response. Any visualized coronary calcific deposit defined an abnormal digital fluorographic response. The sensitivities of digital fluoroscopy (86%) and digital ventriculography (79%) were significantly higher than the sensitivity of thallium (62%) (p less than 0.05). The specificity of thallium (82%) was not significantly higher than that of either digital ventriculography (72%) or fluoroscopy (67%). The diagnostic accuracies of digital fluoroscopy, digital ventriculography, and thallium were 75%, 75% and 73%, respectively. A logistic regression model showed that thallium and digital fluoroscopy were more accurate in younger patients, whereas digital ventriculography was more sensitive in hypertensive persons and in those not taking beta-blocking drugs. The choice of test depends on disease prevalence, clinical variables (such as age and hypertension) and the importance of functional information obtained from stress testing.

Age Factors↗
PubMed1985

Combined cardiac catheterization and carotid cineangiography: an analysis of complications.

Two hundred fifty-three patients underwent cardiac catheterization with selective cineangiography of the carotid arteries. Diagnostic angiograms of both the right and left carotid arteries were obtained in 240 patients (95%). Of these, 217 patients (90%) were studied without complication, 18 (8%) had minor complications, and five (2%) had major complications. Four of the five major complications occurred in patients with bilateral carotid atherosclerosis obliterans. Variations of catheterization technique used in an effort to reduce risk are discussed.

Adult↗
PubMed1985

Anatomical considerations in the design of a long-term implantable human left ventricle assist system.

A permanently implantable left ventricle assist system (LVAS) is being developed and is planned to be implanted in the left chest cavity against the chest wall with the electrohydraulic energy converter placed in a resected rib space. The inflow and outflow pump ports are connected to the left ventricle (LV) apex and to the descending aorta, respectively. Three additional major components of this system consist of the transcutaneous energy transmission system (TETS) (Thermedics), the variable volume device (VVD), and the internal battery. To finalize the design of this integrated system, key anatomical information was obtained by a special radiographic and angiographic study of 31 adult men with a varying degree of coronary artery disease and myocardial dysfunction. These data were combined with the previous computed tomography study by using a standard vertical reference system. The resultant integrated data, which consist of the three-dimensional chest model, the LV apex and axis orientation, rib orientation, chest wall thickness, and the descending aorta location, were used to define the design and anatomical locations of the inflow and outflow pump ports, the VVD, the pump and energy converter orientation, the TETS, and the internal battery. The most critical component for the design was found to be the inflow system. With regard to the average coronary disease patient, an anatomically practical configuration was demonstrated to exist for the presently proposed LVAS. Design flexibility was allowed for some of the critical components in order to fit the system in a large number of patients regardless of the stage and type of the underlying disease.

Adult↗
PubMed1984

Young adults with coronary atherosclerosis: 10 year results of surgical myocardial revascularization.

This study reviews data on 107 patients, aged 35 years or younger, who underwent surgical coronary revascularization from 1971 to 1975. Early clinical events included one operative death and five nonfatal perioperative myocardial infarctions. Late follow-up (mean interval after operation 115 months) demonstrated actuarial survival rates of 94% at 5 years and 85% at 10 years. Fifteen late deaths, 23 nonfatal myocardial infarctions, 13 reoperations and return of severe angina in 10 patients were considered late clinical events. Actuarial survival free of early or late clinical events was 77% at 5 years and 53% at 10 postoperative years. Testing of clinical, angiographic and operative variables for influence on survival and event-free survival showed that survival was decreased by multivessel disease and impaired left ventricular function; event-free survival was decreased by a family history of coronary disease and cigarette smoking. Both survival and event-free survival were decreased by diabetes and elevated serum cholesterol. Postoperative cardiac catheterization (64 patients, mean postoperative interval 47 months) demonstrated that mammary artery graft patency (25 of 27, 93%) exceeded vein graft patency (49 of 88, 56%, p less than 0.01). The atherogenic diatheses of young adults may compromise the operative result, whereas use of internal mammary artery grafts may enhance the palliation of bypass surgery.

Adult↗
PubMed1984

Left ventricular function in coronary artery disease. Evaluation of slope of end-systolic pressure-volume line (Emax) and ratio of peak systolic pressure to end-systolic volume (P/Ves).

Left ventricular function was assessed by measurement of systolic pressure-volume variables and ejection fraction in seven normal subjects (group I), five patients with coronary artery disease and normal symmetric left ventricular wall motion (group II) and eight patients with remote myocardial infarction and segmental akinesia (group III). Left ventricular volumes were obtained from right anterior oblique ventriculograms and pressures from catheter-tip micromanometer (14 patients) or fluid-filled catheters (6 patients) at two different systolic loads. P/Ves was calculated as the ratio of peak systolic pressure (P) to end-systolic volume (Ves) at rest, Emax as the slope of the end-systolic pressure volume line constructed at two systolic loads, and Vo as the volume axis intercept of this line. Emax was significantly (p less than 0.01) lower in patients with segmental akinesia (group III) (5.0 +/- 0.5) than in normal subjects (group I) (10.4 +/- 0.8) or patients with coronary artery disease and normal wall motion (group II) (9.9 +/- 0.8). In contrast, there was no significant difference in P/Ves among the three groups (6 +/- 1.0 in group I, 5 +/- 0.8 in group II, 3.7 +/- 0.5 in group III). Similarly, Ves and Vo failed to separate the three groups. Although ejection fraction was significantly (p less than 0.05) lower in group III (0.56 +/- 0.03) than in groups I and II (0.67 +/- 0.03 in both groups), there was considerable overlap of individual values in the three groups. In eight patients, measurements were repeated during isometric exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Output↗
PubMed1982

Echographic-quantified severity of mitral anulus calcification: prognostic correlation to related hemodynamic, valvular, rhythm, and conduction abnormalities.

Clinical and echocardiographic findings in 123 patients with mitral anulus calcification (MAC) were analyzed. In all patients M-mode echocardiography demonstrated a dense band of echoes posterior to the mitral valve, moving parallel and anterior to the left ventricular endocardium. Thirty-three per cent of patients were classified as having minimal to mild MAC (< 5 mm) and 67% had moderate to severe MAC (greater than or equal to 5 mm). There was a significant correlation between the degree of MAC to left atrial enlargement, congestive heart failure, aortic valve sclerosis, mitral regurgitation, atrial fibrillation, and AV-fascicular conduction defects. ECG evidence of conduction disturbances was significantly associated with MAC greater than or equal to t mm in width. The echocardiographic demonstration of MAC greater than or equal to 5 mm was significantly associated with the clinical implications known to occur with MAC; this echographic finding has important prognostic value in the evaluation of patients with mitral anulus calcification.

Aged↗
PubMed1982

Idiopathic hypertrophic subaortic stenosis and coronary atherosclerosis. Results of coronary artery bypass alone and myectomy combined with coronary artery bypass.

Twenty-one patients with combined coronary artery disease and idiopathic hypertrophic subaortic stenosis (IHSS) have had coronary artery bypass grafting alone (Group I, n = 7) or in combination with left ventricular septal myectomy (Group II, n = 14). Patients ranged in age from 46 to 73 years (mean 59 years). There were no operative deaths, but one Group I patient died 16 months after operation. Patients in Group I have had continuing symptoms after the operation, whereas Group II patients have had consistent relief of symptoms. Patients with documented IHSS and coronary atherosclerosis should undergo combined coronary bypass and septal myectomy if symptoms recur with medical management.

Aged↗
PubMed1981

Progression of coronary atherosclerosis.

Two hundred sixty-two patients with 50% or greater obstruction of at least one coronary artery on the initial study underwent recatheterization 2-182 months later and were evaluated for progressive arterial changes. Progression was considered present if (1) a change from less than total obstruction to total obstruction occurred in any vessel; (2) a change from 70% or less to 90% or more occurred in any vessel; (3) a change from 30% or less to 50% or more occurred in any vessel not initially obstructed by 50%; or (4) a 20% or more increase in obstruction was noted in any vessel already narrowed 50% or more. Of the 262 patients, 116 of 238 men (49%) and 12 of 24 women (50%) met the criteria for progression. Risk factors determined at the time of the initial catheterization in patients who met the criteria for progression were compared with risk factors in patients who did not. No significant difference could be found between the groups in relation to family history, blood pressure, diabetes, smoking habits, weight, cholesterol levels, triglyceride values, initial ECG and initial catheterization findings. The frequency of detecting progressive arterial changes tended to increase as the interval between studies increased (p less than 0.001). The frequency of multiple vessel progression increased as the interval between studies increased. Progression was more frequent in patients younger than 50 years than it was in patients 50 years and older.

Adult↗
PubMed1981

Late clinical and arteriographic results in 500 coronary artery reoperations.

The incidence of coronary artery reoperations averaged 2.7% from 1967 through 1979. In a mean interval of 51 months between operations, three-vessel disease increased from 24% to 63%, and 31% of these 500 consecutive patients lost previously normal left ventricular function. Three angiographic indication groups were identified: (1) progressive coronary atherosclerosis, 247 (51%); (2) graft failure, 147 (29%); and (3) a combination of progressive coronary atherosclerosis and graft failure, 96 (19%). Angina recurred earlier in patient with graft failure, mean 17 months compared with a mean of 37 months for the other groups. Twenty (4%) operative deaths occurred. The series is divided into 387 patients operated upon under normothermic anoxic arrest and 113 with systemic hypothermia and cold cardioplegia. In the cardioplegia group, perioperative myocardial infarction was 2.7% in comparison with 7.8% for patients with anoxic arrest (p = 0.055). The number of grafts per patient increased from 1.0 to 1.9 and blood usage decreased from 11 units to 2.7 units. After a mean follow-up of 42 months, angina was relieved or improved in 86%. Recatheterization of 104 patients after a mean interval of 19 months showed a 79% vein graft patency rate and a 97% mammary artery graft patency rate. Grafting performed for graft failure (47) yielded an 85% patency rate. Actuarial 5 year survival was 87.4% for those with progressive atherosclerosis, 89.4% for patients with graft failure, and 91.5% for the combined indication group. Clinical improvement, graft patency, and long-term survival are nearly equal among the indication groups. Palliation derived from these reoperations approaches that achieved after primary revascularization.

Adult↗