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D C Miller

Publications and source records attributed to D C Miller.

At least 19 recordsLinked to original sources
PubMed1995

Surgical management of aortic dissection during a 30-year period.

BACKGROUND: Certain recent studies have demonstrated improved surgical outcome in patients with aortic dissection. We analyzed the surgical survival rates of patients with acute aortic dissections and the late prognosis of those with aortic dissection during a 30-year period. METHODS AND RESULTS: Between 1963 and 1992, 360 patients (256 men and 104 women; mean +/- 1 SD age, 57 +/- 14 years) underwent surgery for aortic dissection: 174 patients had an acute type A (AcA), 46 an acute type B (AcB), 106 a chronic type A (ChA), and 34 a chronic type B (ChB) aortic dissection. The overall operative mortality rate was 24 +/- 8% (26 +/- 3% for AcA, 39 +/- 8% for AcB, 17 +/- 4% for ChA, and 15 +/- 6% for ChB, [+/- 70% confidence limit]). The operative mortality rates for patients with acute aortic dissection (AcA or AcB) were assessed for five time "windows": 1963 to 1972 (42 +/- 8%), 1973 to 1977 (37 +/- 8%), 1978 to 1982 (15 +/- 6%), 1983 to 1987 (27 +/- 6%), and 1988 to 1992 (26 +/- 6%). Logistic regression analysis suggested that the low operative mortality rate during the 1978-to-1982 interval occurred by chance. Multivariate analysis showed earlier operative year, hypertension, cardiac tamponade, renal dysfunction, and older age were independent determinants of operative death. Actuarial survival rates (including early deaths) after 5, 10, and 15 years for AcA patients were 55%, 37%, and 24%; for AcB, 48%, 29%, and 11%; for ChA, 65%, 45%, and 27%; and for ChB, 59%, 45%, and 27%. Multivariate analysis revealed that older age and previous operation were significant predictors for late death. Freedom from reoperation for all patients was 84%, 67%, and 57% at 5, 10, and 15 years, respectively. CONCLUSIONS: Although the operative mortality rate decreased over time for patients with aortic dissection, the risk for those with acute aortic dissection during the last 10 years (1983 to 1992) is probably more realistic than that observed in the preceding 5-year interval (1978 to 1982). The operative mortality rates for patients with chronic aortic dissection have remained relatively static. Earlier diagnosis of acute aortic dissection before development of cardiac tamponade and renal impairment is critical to improve the operative salvage rate. Long-term outcome still is not optimal, which emphasizes the need for better serial postoperative aortic imaging surveillance and medical follow-up and blood pressure control.

Adult↗
PubMed1995

Left ventricular function, twist, and recoil after mitral valve replacement.

BACKGROUND: Preservation of the mitral subvalvular apparatus during mitral valve replacement (MVR) has become more popular, in part because of the clinically and experimentally demonstrated more optimal left ventricular (LV) performance after surgery; the mechanisms responsible for this beneficial influence, however, have not been clearly elucidated. METHODS AND RESULTS: Fourteen dogs underwent placement of 26 myocardial markers into the LV and septum. One week later, the animals were studied while awake, sedated, and atrially paced (120 beats per minute) both under baseline conditions and after inotropic stimulation (calcium). The animals then underwent MVR and were randomized into either chord-sparing (MVR-Intact) or chord-severing (MVR-Cut) techniques. Two weeks later, the animals were studied under the same conditions. LV systolic function was assessed by the slope of the end-systolic pressure-volume relation (Ees); early LV diastolic filling was analyzed by the pressure-time constant of relaxation (tau). The instantaneous longitudinal gradient of torsional deformation for the LV (twist) was also calculated, as were the changes in twist with respect to time during systole and early diastole (LV recoil). Intergroup comparison showed a trend toward increased contractility (Ees, P = .061, before versus after MVR), as well as faster relaxation for the MVR-Intact group. Concurrent analysis of LV systolic function and the rate of systolic twist revealed a significant inverse relation, which disappeared after MVR when the chordae were severed. CONCLUSIONS: These observations suggest that the mitral subvalvular apparatus acts as a modulator of LV systolic torsional deformation into LV pump (or ejection) performance.

Animals↗
PubMed1995

Post-polio syndrome spinal cord pathology. Case report with immunopathology.

Post-polio syndrome (PPS) describes the clinical onset of progressive muscular weakness many years after survival of acute paralytic poliomyelitis, often in muscle groups clinically unaffected by the original disease process. Prior pathologic descriptions of this often disabling, but not usually fatal, syndrome have been scanty. These have emphasized the presence of persistent or new inflammation in the meninges, spinal cord, and muscles of affected patients. The inflammation suggests several pathogenetic hypotheses, including persistent active poliovirus infection, autoimmune attack on central and peripheral nervous system elements, or increased vulnerability of poliovirus-damaged tissue to new infections. We have recently examined the central nervous system from a PPS patient. The cord showed focal perivascular intraparenchymal chronic inflammatory infiltrates. Immunoperoxidase staining demonstrated that the infiltrates were virtually pure populations of B lymphocytes (immunopositive with antibody L26, and immunonegative with the T cell marker UCHL1 as well as the macrophage marker HAM56). There were rare macrophages (HAM56 immunopositive) and no T cells. The character of the infiltrates suggests that PPS could be an autoimmune disorder mediated by antibodies produced in situ, and not by a cell-mediated process. Additional important pathological features were the presence in the anterior horns of axonal spheroids and of moderate Wallerian degeneration in the lateral columns. The brain was entirely unremarkable, with no detectable cell loss of gliosis in the internal capsules or precentral gyri.

Anterior Horn Cells↗
PubMed1995

Tenascin expression in astrocytomas correlates with angiogenesis.

We investigated the expression and distribution of the extracellular matrix protein tenascin (TN) in 59 astrocytomas and 11 samples of normal brain by Western blot analysis and immunohistochemistry using antibodies against human TN. The tumors included 14 juvenile pilocytic astrocytomas (grade 1), 13 low grade fibrillary astrocytomas (grade II), 8 anaplastic astrocytomas (grade III), and 24 glioblastomas multiforme (grade IV). Proliferation indices were calculated by computer-based image analysis after immunostaining with the MIB-1 antibody against the Ki-67 proliferation-associated antigen. Western blot analysis for TN on fresh frozen tumor tissue from 23 of the 59 astrocytomas indicated up to 4-fold higher TN expression in glioblastomas multiforme than in nontumorous control tissues. Enhanced intercellular expression of TN was observed by immunohistochemistry in glioblastomas multiforme. More-over, TN immunostaining was consistently greater within and around the walls of hyperplastic blood vessels than nonhyperplastic vessels of both high grade tumors and juvenile pilocytic astrocytomas. Juvenile pilocytic astrocytomas with increased TN expression by Western blot analysis had vascular hyperplasia by light microscopy. Proliferation indices moderately correlated with tumor grade. Enhanced immunohistochemical expression of TN was associated with higher tumor grade with higher proliferation indices. The strong association of TN and vascular hyperplasia, regardless of tumor grade, suggests that TN may play a crucial role in angiogenesis.

Astrocytoma↗
PubMed1995

Binswanger's disease presenting as levodopa-responsive parkinsonism: clinicopathologic study of three cases.

We report three cases of autopsy-proven Binswanger's disease (subcortical arteriosclerotic encephalopathy) with unusual clinical features. Two patients had supranuclear gaze disturbances, early gait dysfunction, and speech disorders suggestive of progressive supranuclear palsy. One of these patients was not demented at the time of death. The third patient had features typical of Parkinson's disease. All three patients were responsive to treatment with levodopa. The clinical spectrum of Binswanger's disease should be expanded to include levodopa-responsive parkinsonism.

Aged↗
PubMed1995

Aortic dissection.

Explore the source record for details and available documents.

Aortic Dissection↗
PubMed1995

Durability of the Hancock MO bioprosthesis compared with standard aortic valve bioprostheses.

To compare the durability of the Hancock modified orifice (Hancock MO, model 250 [H-MO]) valve with two other commonly used standard aortic valve bioprostheses, a cohort of 1,602 patients undergoing aortic valve replacement using porcine valves between 1971 and 1990 (excluding simultaneous mitral valve replacement) was analyzed retrospectively using Cox model multivariate techniques. Five hundred sixty-one patients received a composite H-MO valve, 652 received a standard Hancock model 242 (H) valve, and 389 received a Carpentier-Edwards model 2625 (C-E) valve. Mean age was 60 +/- 15 years (+/- 1 standard deviation) (71% male). Follow-up (10,247 patient-years) extended to 15 years and was 97% complete. The main focus of this study was bioprosthetic durability, using The American Association for Thoracic Surgery/The Society of Thoracic Surgeons guidelines to define structural valve deterioration (SVD). Multivariate analysis revealed that (younger) age (p < 10(-5), liver disease (p = 0.02), and 1981 to 1985 operative period (p = 0.012) were the only significant, independent predictors of SVD. In concordance with previous reports, the SVD freedom estimate was greater than 90% at 15 years for patients older than 70 years of age. Hepatic dysfunction had an adverse effect on SVD (estimated freedom from event at 10 years was 34 +/- 17% [standard error of mean] versus 78 +/- 2% for those without liver disease), but this affected only 3% of patients. Interestingly, one operative period (1981 to 1985) was associated with a slightly higher risk of SVD compared to the three other 5-year time windows. Valve type did not emerge as a significant risk factor for SVD.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1995

Pregnancy and bioprostheses: influence on structural valve deterioration.

The long-term performance of bioprostheses was evaluated in women 35 years of age or less to determine the influence of pregnancy on structural valve deterioration. Between 1972 and 1992, 237 female patients received 255 biological prostheses. Of the total operations, 53 were performed in patients who experienced pregnancy (P) and 202 in patients who were never pregnant (nonpregnant [NP]). The mean age of the P group was 23.0 +/- 5.8 years (standard deviation) (12 to 34 years) and of the NP group it was 27.1 +/- 6.3 years (8 to 35 years) (p < 0.05). The mean follow-up for the NP group was 6.8 years and for the P group it was 7.9 years. The late mortality was 2.26%/patient-year overall, 2.71%/patient-year for the NP group and 0.89%/patient-year for the P group (p = not significant [NS]). The P group of 52 patients had 94 pregnancies: 70 deliveries (74.5%) and 24 abortions (25.5%) (therapeutic, 14 [15%]). There were a total of 143 valve-related complications (P, 35; NP, 108); the majority for structural valve deterioration (SVD) 43% (109 patients), P 51% (27 patients) and NP 41% (82 patients) (p = NS). The valve-related reoperation rate paralleled the SVD rate at 42% (107 patients), P 51% (27 patients) and NP 40% (80 patients) (p = NS). The overall reoperative mortality rate was 6.0%. The interval from initial implant to reoperation was 99.6 +/- 3.6 months (p = NS groups P and NP).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Endovascular stent-grafting after arch aneurysm repair using the "elephant trunk".

A 68-year-old woman with severe chronic obstructive pulmonary disease, aortic valvular insufficiency, and diffuse thoracic aortic aneurysm underwent aortic valve replacement and separate Dacron graft replacement of the ascending aortic and arch aneurysms using the elephant trunk technique. She was discharged on the tenth postoperative day. Five months later, she underwent endovascular stent-graft repair of the descending thoracic aortic aneurysm. She recovered uneventfully, and was discharged on the third postoperative day. Follow-up computed tomography at 6 months demonstrated exclusion of all flow into the descending thoracic aortic aneurysm. The elephant trunk technique followed by endovascular stent-grafting of the descending thoracic component is a potential therapeutic option in selected high-risk patients with diffuse aortic aneurysmal disease.

Aged↗
PubMed1995

A method to assess endocardial regional longitudinal curvature of the left ventricle.

Knowledge of the instantaneous geometry of the left ventricular (LV) chamber is necessary to calculate LV function and wall stresses. We describe a method utilizing myocardial markers that does not rely on any a priori assumptions of global LV geometry. Five dogs underwent placement of 25 endocardial and 3 epicardial miniature LV markers. Six weeks later, the animals were studied during conscious closed-chest conditions. The three-dimensional coordinates of the LV markers were used to compute longitudinal fitted curves for LV walls and septum during steady-state conditions; endocardial radii of curvature (rcurv) were then computed for each region at the midequatorial (rcurv-eq) and apical levels. There was a uniform decrease in rcurv in each LV wall during systole (compared with diastole, P < 0.01); at end systole, rcurv was regionally heterogeneous between opposing walls, e.g., anterior and posterior rcurv-eq values were 17.2 +/- 2.0 and 17.7 +/- 1.8 (SD) cm, respectively (P < 0.05). At end diastole, only septal-lateral rcurv-eq was different (16.9 +/- 2.1 vs. 18.7 +/- 1.3 cm: P < 0.05). Normalization of rcurv (to instantaneous LV volume) removed the systolic-diastolic differences, but a similar pattern of regional heterogeneity persisted. The data presented pertain to the LV endocardial surface, but the method described can be applied to the epicardial surface as well; this new method offers promise in assessing dynamic changes in longitudinal LV endocardial curvature.

Analysis of Variance↗
PubMed1995

Hypothalamic hamartoma and the Pallister-Hall syndrome.

The Pallister-Hall syndrome (PHS) was initially described as the congenital hypothalamic 'hamartoblastoma' syndrome in 1980. Cardinal manifestations of the syndrome consist of a hypothalamic hamartoma and extracranial abnormalities, initially thought to be fatal in the perinatal period. The original pathologic description of these hypothalamic lesions were from infants who died in the perinatal period and revealed small cells of variable density which resembled primitive undifferentiated germinal cells and appeared to invade the hypothalamic nuclei, suggesting a neoplastic potential. Hypothalamic lesions have now been removed from older infants and children with this syndrome and reveal a more mature histologic appearance typical of a hypothalamic hamartoma. We present 2 new cases of PHS who underwent surgery and demonstrate the maturational nature of the hypothalamic lesion and the phenotypic variability of the syndrome.

Abnormalities, Multiple↗
PubMed1995

The hippocampus in aging and Alzheimer's disease.

The role of imaging in the evaluation of neurodegenerative disorders is summarized. The primary role of imaging is to exclude potentially treatable disorders such as meningioma, extracerebral hematoma, Wernicke's disease, and hypothyroidism. Atrophic changes dominate in the hippocampal region on Alzheimer's disease versus the anterior, frontal, and temporal lobes in Pick's disease. Signal hypointensity in the putamen on T2-weighted spin-echo images favors poorly drug-responsive Parkinson's disease whereas putaminal hyperintensity is observed with Creutzfeldt-Jacob, Wilson's, and Leigh's diseases. As our population ages, a thorough understanding of imaging findings in a geriatric population assumes an increasing importance.

Aged↗
PubMed1995

A Gly1127Ser mutation in an EGF-like domain of the fibrillin-1 gene is a risk factor for ascending aortic aneurysm and dissection.

Ascending aortic disease, ranging from mild aortic root enlargement to aneurysm and/or dissection, has been identified in 10 individuals of a kindred, none of whom had classical Marfan syndrome (MFS). Single-strand conformation analysis of the entire fibrillin-1 (FBN1) cDNA of an affected family member revealed a G-to-A transition at nucleotide 3379, predicting a Gly1127Ser substitution. The glycine in this position is highly conserved in EGF-like domains of FBN1 and other proteins. This mutation was present in 9 of 10 affected family members and in 1 young unaffected member but was not found in other unaffected members, in 168 chromosomes from normal controls, and in 188 chromosomes from other individuals with MFS or related phenotypes. FBN1 intragenic marker haplotypes ruled out the possibility that the other allele played a significant role in modulating the phenotype in this family. Pulse-chase studies revealed normal fibrillin synthesis but reduced fibrillin deposition into the extracellular matrix in cultured fibroblasts from a Gly1127Ser carrier. We postulate that the Gly1127Ser FBN1 mutation is responsible for reduced matrix deposition. We suggest that mutations such as this one may disrupt EGF-like domain folding less drastically than do substitutions of cysteine or of other amino acids important for calcium-binding that cause classical MFS. The Gly1127Ser mutation, therefore, produces a mild form of autosomal dominantly inherited weakness of elastic tissue, which predisposes to ascending aortic aneurysm and dissection later in life.

Adult↗
PubMed1994

Transluminal placement of endovascular stent-grafts for the treatment of descending thoracic aortic aneurysms.

BACKGROUND: The usual treatment for thoracic aortic aneurysms is surgical replacement with a prosthetic graft, but the associated morbidity and mortality are considerable. We studied the use of transluminally placed endovascular stent-graft devices as an alternative to surgical repair. METHODS: We evaluated the feasibility, safety, and effectiveness of transluminally placed stent-graft to treat descending thoracic aortic aneurysms in 13 patients over a 24-month period. Atherosclerotic, anastomotic, and post-traumatic true or false aneurysms and aortic dissections were treated. The mean diameter of the aneurysms was 6.1 cm (range, 5 to 8). The endovascular stent-grafts were custom-designed for each patient and were constructed of self-expanding stainless-steel stents covered with woven Dacron grafts. RESULTS: Endovascular placement of the stent-graft prosthesis was successful in all patients. There was complete thrombosis of the thoracic aortic aneurysm surrounding the stent-graft in 12 patients, and partial thrombosis in 1. Two patients initially had small, residual patent proximal tracts into the aneurysm sac, but both tracts thrombosed within two months after the procedure. In four patients, two prostheses were required to bridge the aneurysm adequately. There have been no deaths or instances of paraplegia, stroke, distal embolization, or infection during an average follow-up of 11.6 months. One patient with an extensive chronic aortic dissection required open surgical graft replacement four months later because of progressive dilatation of the arch. CONCLUSIONS: These preliminary results demonstrate that endovascular stent-graft repair is safe in highly selected patients with descending thoracic aortic aneurysms. This new method of treatment will, however, require careful long-term evaluation.

Adult↗
PubMed1994

Pathology with clinical correlations of primary central nervous system non-Hodgkin's lymphoma. The Massachusetts General Hospital experience 1958-1989.

BACKGROUND: Primary central nervous system non-Hodgkin's lymphoma (NHL-CNS) is an enigmatic disease of uncertain origin. At the Massachusetts General Hospital, 104 patients with NHL-CNS were seen from 1958 through 1989. An impression of changes in the frequency of diagnosis, character of the tumors, and therapy for this disease prompted this study of the pathologic features, clinical data, and natural history of this tumor in these 104 patients. METHODS: Histologic slides (neurosurgical specimens and autopsy tissues) were available for 99 patients. The tumors were classified by the Working Formulation classification. Immunostaining data and all clinical data were retrieved from the relevant offices and hospital charts. RESULTS: Primary central nervous system non-Hodgkin's lymphoma tripled in frequency (5.66 cases per year in 1978-89 versus 1.75 cases per year in 1958-77) and now represents 6.6% of all primary brain neoplasms (versus 3.3% before 1978; chi 2 = 17.52, P < 0.01). For the 99 tumors histologically classified, 89% were high grade. Intermediate grade lymphomas, once the second most common subtype, have disappeared since 1983. All tumors had diffuse architecture; 77% (including all 11 patients with acquired immune deficiency syndrome) were large cell subtypes. Two cases were intravascular lymphoma. With one exception, all of the 41 tumors evaluated were B-cell types; 32 of 40 had monotypic surface immunoglobulin. There was 1 T-cell lymphoma. Of 64 tumor recurrences, 29 were at the initially defined site; 12 were in the leptomeninges, 29 were in other sites in the neuraxis, and 8 were in systemic sites. Systemic metastases have not occurred since 1984. Median survival for the 68 patients who survived after diagnostic surgery and for whom follow-up information could be obtained was 19 months; 9 months for those with high grade tumors and 30.5 months for those with intermediate grade tumors. This difference was not significant (P = 0.13). A separate set of seven patients had focal tumorlike lymphoid infiltrates composed of benign-appearing lymphocytes, which were associated with good long term survival. The differential histologic diagnosis of NHL-CNS was occasionally difficult, and the spectrum of this differential was broader than generally stated. CONCLUSIONS: Primary central nervous system non-Hodgkin's lymphoma has increased in frequency even in nonimunocompromised patient populations. This increase has been accompanied by the disappearance of intermediate grade histologic types, suggesting a fundamental shift in the biology of the neoplasms. The introduction of chemotherapeutic regimens appears to have altered the natural history such that systemic metastases outside the central nervous system no longer occur, and there are now some long term survivors of this formerly uniformly fatal disease.

Brain Neoplasms↗
PubMed1994

Experimental evaluation of different chordal preservation methods during mitral valve replacement.

During chordal-sparing mitral valve replacement (MVR), some recommend anatomic reattachment of the anterior leaflet chordae to the anterior annulus; others advocate shifting the chordae to the posterior annulus. To compare the results of these techniques with those of conventional MVR (total chordal excision), 21 dogs were studied 5 to 12 days after implantation of tantalum markers to measure left ventricular volume and geometry. One to 3 weeks later, animals underwent conventional MVR (n = 7) or chordal-sparing MVR with either anterior chordal reattachment (n = 7) or posterior transposition (n = 7). Contractility was assessed using physiologic volume intercepts for end-systolic elastance, preload recruitable stroke work, and the relationship of the maximum rate of change of left ventricular pressure to the end-diastolic volume. The physiologic intercept for end-systolic elastance did not change after anterior or posterior MVR, but increased from 60 +/- 14 mL before MVR to 72 +/- 17 mL with conventional MVR (p < 0.002), indicating impaired left ventricular contractility. Similarly, the physiologic intercept for preload recruitable stroke work and the relationship of the maximum rate of change of left ventricular pressure to the end-diastolic volume increased 22% +/- 13% and 28% +/- 13%, respectively, after conventional MVR, but neither changed after anterior or posterior MVR. Although the end-diastolic pressure-volume relationship did not change with either chordal-sparing technique, its slope increased 98% +/- 73% after conventional MVR (p < 0.008). Thus, although chordal preservation maintained better systolic and diastolic function, there was no substantial difference between the results of the anterior and posterior chordal-sparing techniques in this model.

Animals↗
PubMed1994

Pilot study of the efficacy of a thrombin inhibitor for use during cardiopulmonary bypass.

Heparin is normally used for anticoagulation during cardiopulmonary bypass (CPB), but its use is contraindicated in patients with a history of heparin-induced thrombocytopenia, heparin-provoked thrombosis, or both. Heparin therapy can also be ineffective due to heparin resistance. A short-acting, oligonucleotide-based thrombin inhibitor (thrombin aptamer) may potentially serve as a substitute for heparin in these and other clinical situations. We tested a novel thrombin aptamer in a canine CPB pilot study to determine its anticoagulant efficacy, the resultant changes in coagulation variables, and the aptamer's clearance mechanisms and pharmacokinetics. Seven dogs were studied initially: Four received varied doses of the aptamer (to establish the pharmacokinetic profile) and 3 received heparin. Subsequently, 4 other dogs underwent CPB, receiving a constant infusion of the aptamer before CPB (to characterize the baseline coagulation status), with partial CPB and hemodilution, during 60 minutes of total CPB, and, finally, after a 2-hour recovery period. At a 0.5 mg.kg-1.min-1 dose, the activated clotting time rose with aptamer infusion from 106 +/- 12 seconds to 187 +/- 8 seconds (+/- 1 standard deviation) (p = 0.014), increased further with hemodilution (to 259 +/- 41 seconds; p = 0.017), and was even more prolonged during total CPB (> 1,500 seconds; p < 0.001). This later increase in the activated clotting time paralleled a rise in the plasma concentration of the thrombin aptamer during total CPB, as determined by high-performance liquid chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗