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Biomedical subjects

C M Otto

Publications and source records attributed to C M Otto.

At least 19 recordsLinked to original sources
PubMed1999

Valvular disease in the elderly.

As the incidence of valvular disease in the elderly is increasing, understanding of its pathogenesis and natural progression as well as surgical approaches and device technologies are improving. Future studies are needed to develop medical interventions that slow or halt the degenerative valvular processes associated with aging. In addition, mechanical approaches with lower operative risks should be explored and the search should continue for a valve substitute that is durable, hemodynamically efficient, easy to implant, and does not require anticoagulation. Hopefully, future intervention trials will include quality of life assessments such as symptoms, functional capacity and perceptions of well being. At present, the degenerative valvular processes must be followed closely by the clinician, and individual management decisions for the elderly based on the type and severity of valve disease, comorbid medical conditions, and the risks and benefits of intervention, along with patient preferences, rather than on the chronologic age of the patient. It is becoming clear that both survival and quality of life outcomes can improve by consideration of surgery at the onset of indications, before further deterioration eliminates the opportunity to provide benefit for the elderly patient with valvular disease.

Aged↗
PubMed1999

Physical examination in valvular aortic stenosis: correlation with stenosis severity and prediction of clinical outcome.

BACKGROUND AND METHODS: The goal of this study was to examine the ability of physical examination to predict valvular aortic stenosis severity and clinical outcome in 123 initially asymptomatic subjects (mean age 63 +/- 16 years, 70% men) followed up for a mean of 2.5 +/- 1.4 years. RESULTS: Doppler aortic jet velocity correlated with systolic murmur intensity (P =.003) and timing (P =.0002), a single second heart sound (P =.01), and carotid upstroke delay (P <.0001) and amplitude (P <.0001). However, no physical examination findings had both a high sensitivity and a high specificity for the diagnosis of severe valvular obstruction. Clinical end points were reached in 56 subjects (46%), including 8 deaths and 48 valve replacements for symptom onset. Univariate predictors of outcome included carotid upstroke delay (P =.0008) and amplitude (P =.0006), systolic murmur grade (P <.0001) and peak (P =.0003), and a single second heart sound (P =.003). On multivariate Cox regression analysis, the only physical examination predictor of outcome was carotid upstroke amplitude (P =.0001). CONCLUSIONS: Although physical examination findings correlate with stenosis severity, echocardiography still is needed to exclude severe obstruction reliably when this diagnosis is suspected.

Aortic Valve Stenosis↗
PubMed1998

Aortic stenosis. Clinical evaluation and optimal timing of surgery.

Aortic valve disease is common in the elderly with recent data suggesting that aortic sclerosis and stenosis are the end-stage of an active disease process. Aortic atenosis may be diagnosed at symptom onset (angina, heart failure or syncope) but often the diagnosis is suspected in an asymptomatic patient with a systolic murmur. The diagnosis can be confirmed and disease severity evaluated reliably using Doppler echocardiography. Symptomatic severe aortic stenosis is treated with valve replacement, even in the elderly, due to the extremely poor prognosis without relief of outflow obstruction. Management is controversial when there is coexisting moderate aortic stenosis and left ventricular systolic dysfunction.

Aortic Valve↗
PubMed1998

Left ventricular shape analysis from three-dimensional echocardiograms.

The objective of this study was to develop and validate a three-dimensional technique of left ventricular shape analysis. Geometric phantoms and left ventricles of excised calf hearts, normal human subjects, and one subject each with aortic stenosis and dilated cardiomyopathy were reconstructed from three-dimensional echocardiograms. The fit between the reconstructions and true surfaces of the geometric phantoms and excised ventricles was determined. To evaluate in vivo left ventricular shape, a center axis was constructed from the centroid of the mitral annulus to the furthest endocardial point. Regional shape was evaluated as the relative distances of 16 separate myocardial segments from the center axis compared with a population-derived mean value. Global shape was evaluated as the average standard deviation from the normal value over the 16 segments. The system precisely reproduced the shapes of the phantoms and excised left ventricles (root-mean-square error between true and reconstructed surface 1.0 0.2 mm and 1.2 0.8 mm, respectively). The in vivo shape analysis differentiated the pathological from normal left ventricles.

Adult↗
PubMed1998

Three-dimensional measurement of the mitral annulus by multiplane transesophageal echocardiography: in vitro validation and in vivo demonstration.

Ten phantoms were scanned with a multiplane transesophageal echocardiographic probe in a water bath to assess a new method for three-dimensional modeling of the mitral annulus. The annulus was reconstructed from manually outlined borders with Fourier series in each of the three spatial coordinates. Comparisons with direct measurements by least-squares linear regression gave coefficients of determination of 0.99 for annular height, area, and circumference. Expressed as a percentage of their true values, the mean +/- SD of the errors were -0.1% +/- 3.0% for annular height, -2.8% +/- 3.1% for area, and -0.2% +/- 1.7% for circumference. The mean residual error length for phantoms was 0.64 mm compared with 1.21 mm in nine patients studied during general anesthesia. This method gives accurate and precise measurements of the mitral annulus in vitro and should be valuable for studying its morphology and dynamics in vivo.

Adult↗
PubMed1998

Longitudinal assessment of valvular heart disease by echocardiography.

Over the past few years, important publications have addressed the issue of longitudinal assessment of valvular heart disease. The American College of Cardiology and the American Heart Association jointly published guidelines on echocardiography. Aortic stenosis continues to be well studied, with papers characterizing the rates of progression of mean and peak gradients, as well as aortic valve area changes. Doppler assessment of the progression of aortic regurgitation has been shown in larger studies than have been performed in the past. Based on an important study in patients with chronic aortic regurgitation, the optimal timing of surgery in asymptomatic mild to moderate aortic regurgitation may be predicted by indices of left ventricular function and left ventricular stress. Finally, mitral stenosis and mitral regurgitation studies evaluated rates of progression and also optimal timing for surgery.

Cardiac Surgical Procedures↗
PubMed1998

System for quantitative three-dimensional echocardiography of the left ventricle based on a magnetic-field position and orientation sensing system.

Accurate measurement of left-ventricular (LV) volume and function are important to monitor disease progression and assess prognosis in patients with heart disease. Existing methods of three-dimensional (3-D) imaging of the heart using ultrasound have shown the potential of this modality, but each suffers from inherent restrictions which limit its applicability to the full range of clinical situations. We have developed a technique for image acquisition using a magnetic-field system to track the 3-D echocardiographic imaging planes and 3-D image analysis software including the piecewise smooth subdivision method for surface reconstruction. The technique offers several advantages over existing methods of 3-D echocardiography. The results of validation using in vitro LV's show that the technique allows accurate measurement of LV volume and anatomically accurate 3-D reconstruction of LV shape and is, therefore, suitable for analysis of regional as well as global function.

Algorithms↗
PubMed1997

Prospective study of asymptomatic valvular aortic stenosis. Clinical, echocardiographic, and exercise predictors of outcome.

BACKGROUND: Only limited data on the rate of hemodynamic progression and predictors of outcome in asymptomatic patients with valvular aortic stenosis (AS) are available. METHODS AND RESULTS: In 123 adults (mean age, 63 +/- 16 years) with asymptomatic AS, annual clinical, echocardiographic, and exercise data were obtained prospectively (mean follow-up of 2.5 +/- 1.4 years). Aortic jet velocity increased by 0.32 +/- 0.34 m/s per year and mean gradient by 7 +/- 7 mm Hg per year; valve area decreased by 0.12 +/- 0.19 cm2 per year. Kaplan-Meier event-free survival, with end points defined as death (n = 8) or aortic valve surgery (n = 48), was 93 +/- 5% at 1 year, 62 +/- 8% at 3 years, and 26 +/- 10% at 5 years. Univariate predictors of outcome included baseline jet velocity, mean gradient, valve area, and the rate of increase in jet velocity (all P < or = .001) but not age, sex, or cause of AS. Those with an end point had a smaller exercise increase in valve area, blood pressure, and cardiac output and a greater exercise decrease in stroke volume. Multivariate predictors of outcome were jet velocity at baseline (P < .0001), the rate of change in jet velocity (P < .0001), and functional status score (P = .002). The likelihood of remaining alive without valve replacement at 2 years was only 21 +/- 18% for a jet velocity at entry > 4.0 m/s, compared with 66 +/- 13% for a velocity of 3.0 to 4.0 m/s and 84 +/- 16% for a jet velocity < 3.0 m/s (P < .0001). CONCLUSIONS: In adults with asymptomatic AS, the rate of hemodynamic progression and clinical outcome are predicted by jet velocity, the rate of change in jet velocity, and functional status.

Aged↗
PubMed1997

Clinical factors associated with calcific aortic valve disease. Cardiovascular Health Study.

OBJECTIVES: The aim of this study was to determine the prevalence of aortic sclerosis and stenosis in the elderly and to identify clinical factors associated with degenerative aortic valve disease. BACKGROUND: Several lines of evidence suggest that degenerative aortic valve disease is not an inevitable consequence of aging and may be associated with specific clinical factors. METHODS: In 5,201 subjects > or = 65 years of age enrolled in the Cardiovascular Health Study, the relation between aortic sclerosis or stenosis identified on echocardiography and clinical risk factors for atherosclerosis was evaluated by using stepwise logistic regression analysis. RESULTS: Aortic valve sclerosis was present in 26% and aortic valve stenosis in 2% of the entire study cohort; in subjects > or = 75 years of age, sclerosis was present in 37% and stenosis in 2.6%. Independent clinical factors associated with degenerative aortic valve disease included age (twofold increased risk for each 10-year increase in age), male gender (twofold excess risk), present smoking (35% increase in risk) and a history of hypertension (20% increase in risk). Other significant factors included height and high lipoprotein(a) and low density lipoprotein cholesterol levels. CONCLUSIONS: Clinical factors associated with aortic sclerosis and stenosis can be identified and are similar to risk factors for atherosclerosis.

Aged↗
PubMed1997

Characteristics and management of gunshot wounds in dogs and cats: 84 cases (1986-1995).

OBJECTIVE: To determine history, signalment, physical examination findings, treatment, complications, outcome, and prognostic indicators of dogs and cats treated for gunshot wounds at an urban veterinary referral hospital. DESIGN: Retrospective study. ANIMALS: 82 dogs and 2 cats. RESULTS: Young (< 3 years old) sexually intact males were overrepresented. Of the 122 injuries, 52 were to limbs (23/52 were associated with fractures), 32 involved the thorax, 14 involved the abdomen, 14 involved the head, 6 involved the neck, and 4 involved the vertebral column. Seven animals were euthanatized because of financial concerns. Of the remaining 77, 11 died and 66 were discharged from the hospital. Conservative treatment was adequate for animals with limb injuries not associated with a fracture. However, animals with evidence of peritoneal penetration required an exploratory laparotomy. Animals with thoracic injuries usually could be managed with conservative treatment or thoracocentesis. Only 1 animal underwent thoracotomy. Wound infection developed in 4 animals. Initial treatment of animals with gunshot wounds should include administration of antibiotics effective against gram-positive and -negative bacteria. CLINICAL IMPLICATIONS: Most dogs with gunshot wounds that receive adequate treatment can be expected to survive. However, dogs with vertebral column or abdominal wounds may have a worse prognosis than dogs with thoracic or limb injuries.

Abdominal Injuries↗
PubMed1997

Quantitative three-dimensional echocardiography by rapid imaging from multiple transthoracic windows: in vitro validation and initial in vivo studies.

Three-dimensional echocardiography has demonstrated superiority over two-dimensional techniques in the determination of left ventricular mass and volumes. We describe a technique based on a magnetic tracking system which provides rapid three-dimensional image acquisition from multiple acoustic windows. Interactive three-dimensional border tracking and reconstruction with a piecewise smooth subdivision model accurately reproduced phantom volume (calculated volume = 1.00 true volume - 0.6 ml, r = 1.000, standard error of the estimate = 1.3 ml), in vitro heart volume (calculated volume = 1.02 true volume - 1.3 ml, r = 1.000, standard error of the estimate = 0.4 ml), in vitro heart mass (calculated mass = 0.98 true mass + 1.4 gm, r = 0.998, standard error of the estimate = 2.5 gm), and in vivo stroke volume (calculated stroke volume = 1.18 Doppler stroke volume - 17.9 ml, r = 0.990, standard error of the estimate = 2.8 ml). The three-dimensional in vivo data sets, which include views from three acoustic windows, were acquired in less than 90 seconds. We conclude that this method of three-dimensional echocardiographic data acquisition and analysis overcomes limitations inherent in currently available systems.

Animals↗
PubMed1997

The effect of normalization in reducing variability in regional wall thickening.

This study was performed to evaluate a new method for measuring regional left ventricular wall thickening in terms of its variability, normal range, and diagnostic sensitivity. Two-dimensional echocardiographic images in the parasternal short-axis view of 44 normal patients and 17 patients with recent myocardial infarction were analyzed. Regional wall thickness was measured according to the centerline method at 100 chords. Wall thickening at each chord i was calculated as the change in wall thickness between end diastole and end systole at chord i, normalized by the average end-diastolic thickness of the wall segment extending from chord (i - n) to chord (i + n). Five widths of the normalization segment, defined as (2n + 1), were tested: 1 (baseline method), 5, 11, 15, and 21 chords. Widening the normalization segment significantly reduced point-to-point variability by up to 20% (p = 0.0001) evenly over the entire left ventricular contour. The magnitude of reduction approached a plateau at a normalization segment width of 11 chords. The normal mean and standard deviation for regional wall thickening were also reduced slightly but significantly in a progressive and uniform manner. The apparent severity of hypokinesis worsened by up to 0.1 +/- 0.1 SD (p = 0.006) as the normalization segment was widened. The circumferential extent of hypokinesis was not lengthened significantly until the normalization segment was 21 chords wide. The magnitude of hyperkinesis was unchanged. Normalizing over a wider segment of the myocardium reduces variability in the measurement of wall thickening, widens the separation between normal patients and those with disease, and enhances the diagnostic accuracy of quantitative two-dimensional echocardiography. The optimal normalization segment width is 11 chords.

Echocardiography↗
PubMed1997

Production of polyclonal antibodies to feline tumor necrosis factor.

Two 13-amino-acid peptides were synthesized based on the putative feline tumor necrosis factor (FeTNF) sequence. The synthesized peptides were conjugated to keyhole limpet hemocyanin, emulsified in complete Freund's adjuvant, and injected into rabbits. The gene for FeTNF was cloned into the FLAG (International Biotechnologies Inc. [IBI], Kodak, New Haven, Conn.) fusion protein expression vector. The expressed fusion protein was purified by using the M-1 anti-FLAG octapeptide monoclonal antibody (IBI, Kodak). The fusion protein was emulsified in complete Freund's adjuvant and injected into chickens. The immune sera generated to the synthetic peptides and the fusion protein recognized the recombinant FeTNF fusion protein on Western or dot blot assay. The preimmune and immune sera were incubated with naturally occurring FeTNF (supernatants from lipopolysaccharide-stimulated cultured feline peritoneal exudate or peripheral mononuclear cells). The antibody raised to the recombinant FeTNF fusion protein and N-terminal synthetic peptide neutralized bioactivity of native FeTNF and recombinant human TNF. Preimmune sera did not have any neutralizing activity. The polyclonal antibodies were not specific for FeTNF, since both porcine and human recombinant TNF were neutralized by the fusion protein antibodies. The synthetic peptide antibodies recognized recombinant feline and equine TNF on a Western blot.

Animals↗
PubMed1997

Effects of aortic valve replacement on exercise duration and functional status in adults with valvular aortic stenosis.

OBJECTIVE: To evaluate the effect of aortic valve replacement on left ventricular function, functional status and exercise duration in an adult population with valvular aortic stenosis. DESIGN: Prospective study of initially asymptomatic patients with pre- and postvalve replacement echocardiography, functional status score and exercise data. SETTING: University-affiliated, tertiary care teaching hospital. PATIENTS: Valvular aortic stenosis patients referred from academic and private practice internists and cardiologists (n = 34, 65% men, mean age 68 +/- 11 years, preoperative aortic valve area 0.9 +/- 0.4 cm2). INTERVENTIONS: Annual Doppler echocardiography, functional status questionnaires and, if possible, Bruce protocol maximal exercise tolerance tests. MAIN RESULTS: Aortic valve replacement resulted in a decrease in maximum jet velocity (pre 4.7 +/- 0.7 versus post 2.9 +/- 0.7 m/s, P = 0.0001) and left ventricular mass (pre 167 +/- 37 versus post 134 +/- 32 g, P = 0.0001) and an increase in left ventricular ejection fraction (pre 65 +/- 11 versus post 69 +/- 10%, P = 0.05) at rest. However, there was no change in the ratio of early to atrial diastolic filling velocities (pre 1.2 +/- 0.5 versus post 1.4 +/- 0.8, not significant), exercise tolerance as assessed by estimated functional aerobic impairment (pre 26 +/- 32 versus post 22 +/- 27%, not significant) or functional status score (pre 89 +/- 13 versus post 91 +/- 11, not significant). CONCLUSIONS: When the aortic valve is replaced promptly at symptom onset, despite improvement in resting left ventricular systolic performance, there is no evidence of improvement in exercise capacity or functional status.

Aged↗
PubMed1996

Gender differences in left ventricular function at rest and with exercise in asymptomatic aortic stenosis.

In 29 women and 53 men with asymptomatic aortic stenosis, two-dimensional (2-D) and Doppler echocardiography were performed at rest and immediately after treadmill exercise testing to examine gender differences in left ventricular geometry, systolic and diastolic function, functional status, and exercise capacity. Aortic stenosis severity was similar between men and women. Women reported more functional impairment than men (88% +/- 14% vs 95% +/- 7%; p = 0.02). When indexed to body surface area, women had a smaller end-diastolic volume (39 +/- 14 vs 50 +/- 15 ml/m2; p = 0.002), end-systolic volume (13 +/- 6 ml/m2 vs 18 +/- 9 ml/m2; p = 0.01) and left ventricular mass (73 +/- 26 gm/m2 vs 84 +/- 21 gm/m2; p = 0.05), but a higher relative wall thickness in systole (1.5 +/- 0.4 cm vs 1.3 +/- 0.4 cm; p = 0.05), and fractional shortening (43% +/- 7% vs 39% +/- 10%; p = 0.03). Women had higher early and late transmitral velocities than did men (early, 92 +/- 24 cm/sec vs 79 +/- 29 cm/sec; p = 0.05; late, 97 +/- 30 cm/sec vs 68 +/- 23 cm/sec; p < 0.0001), a higher time-velocity integral in early diastole (18.2 +/- 4.8 cm vs 15.1 +/- 4.3 cm; p = 0.006), a significantly shorter exercise duration (4.5 +/- 4.1 minutes vs 8.0 +/- 3.9 minutes; p < 0.0001), a greater degree of functional aerobic impairment (25% +/- 48% vs 2% +/- 33%; p = 0.02), and a smaller increase in cardiac output with exercise (5.4 +/- 3.5 L/min vs 8.0 +/- 4.3 L/min; p = 0.01), in spite of similar peak heart rate and blood pressure responses. In these asymptomatic subjects with aortic stenosis, women had smaller, relatively hypercontractile ventricles, a different diastolic filling profile, more exercise limitation, and poorer functional capacity. These findings demonstrate the importance of gender in the response of the left ventricle to chronic pressure overload.

Adult↗
PubMed1996

Aortic valve disease.

There have been several significant advances in our understanding of aortic valve disease over the past year. Recent studies suggest that "degenerative" valvular aortic stenosis is an active disease process rather than an inevitable consequence of aging. In the diagnostic evaluation of patients with aortic stenosis, detailed studies of the changes in valve area with changes in flow rate and the subaortic flow profile have been performed. In addition, the myocardial response to chronic pressure overload has been studied in further detail including gender differences in the response to chronic pressure overload. Aortic regurgitant severity can now be quantitated more precisely using simplified measures of regurgitant fraction based on Doppler and color flow imaging techniques. The optimal timing of surgical repair in chronic aortic regurgitation continues to be a topic of interest, with additional studies recommending surgical intervention prior to the development of an irreversible decrease in left ventricular contractility. Most importantly, two randomized trials of afterload reduction for preventing left ventricular dilation and symptom onset in aortic regurgitation have been performed, with the data supporting long-term afterload reduction in this patient group.

Aortic Valve Insufficiency↗
PubMed1996

Aortic root complications in Marfan's syndrome: identification of a lower risk group.

OBJECTIVES: The purpose of this study was to examine clinical and echocardiographic predictors of outcome in a cohort of patients with Marfan's syndrome. BACKGROUND: Serial echocardiographic measurements of aortic root dimensions are an important clinical method for monitoring patients with Marfan's syndrome. However, there are few data on the prognostic importance of echocardiographic variables for risk stratification and timing of aortic root replacement. METHODS: In 89 consecutive patients with Marfan's syndrome (age range 1-54 years) clinical and serial echocardiographic data (n = 62) were evaluated as potential predictors of outcome (mean (range) follow up 4 (< 1-16) years). Aortic sinus diameter and an aortic ratio normalised for age and body surface area were examined using Kaplan-Meier life table and Cox regression analysis, with the end point defined as death or surgery for ascending aortic dissection and events defined as an end point or surgery for ascending aortic aneurysm. RESULTS: Overall actuarial survival at two and five years was 96% and 92% and event free survival was 85% and 76%, respectively. There were five deaths due to aortic dissection, four patients survived surgery for ascending dissection, and nine underwent root replacement with a composite graft for ascending aneurysm. Those with aortic events were older (35 (12) v 25 (13) years, P = 0.007) and had greater initial aortic root dimensions (47 (14) v 33 (8) mm, P < 0.0001) and ratios (1.6 (0.5) v 1.3 (0.2), P < 0.0001). In the 62 patients with serial echocardiographic follow up, the rate of aortic root dilatation was more rapid in those with events (15 (17) v 0 (3)%/year, P < 0.0001). Utilising a Cox proportional hazards model, the groups with an initial aortic ratio > or = 1.3 or an annual change in aortic ratio > or = 5% had a relative risk of an aortic complication of 2.7 and 4.1, respectively (95% confidence limits 1.5 to 4.8 and 1.8 to 9.3). Only one of 31 patients with an initial aortic ratio of < 1.3 and a rate of change of < 5% had an event (five year event free survival 97%). CONCLUSIONS: A low risk subgroup of patients with Marfan's syndrome can be identified as those with an aortic ratio < 1.3 and an annual change in aortic ratio of < 5%. These findings are helpful in optimising echocardiographic monitoring and risk stratification of patients with Marfan's syndrome.

Adolescent↗