Post-hospital course and complications following coronary bypass surgery.
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Adult↗
Biomedical subjects
D M Cosgrove
Publications and source records attributed to D M Cosgrove.
Visualization of acute pulmonary emboli by transesophageal echocardiography.
This report describes a patient who became hypoxic and hypotensive while awaiting cardiac surgery. An urgent transesophageal echocardiogram in the operating room showed a mass at the junction of the main and right pulmonary arteries consistent with thrombus. The thrombus was removed surgically, and the patient then had a successful aortic valve replacement. Transesophageal echocardiography is therefore useful in the evaluation of the critically ill patient.
Acute Disease↗
Color Doppler and two-dimensional echocardiographic determination of the mechanism of aortic regurgitation with surgical correlation.
The character of the color flow Doppler jet provides information on the mechanism and pathologic elements of valve dysfunction. This has been useful in the evaluation of mitral regurgitation, a repairable problem, but has not been described comprehensively for the aortic valve. The purpose of our study was to correlate the color flow Doppler characteristics of the aortic regurgitant jet and two-dimensional echocardiographic findings of valve mobility with surgical pathology. Prepump intraoperative echocardiography and color flow Doppler echocardiography were performed on 124 patients with aortic regurgitation and used to categorize leaflet motion as excessive, restricted, or normal, jet direction as eccentric or central, and jet origin between the cusps as eccentric, central, or diffuse. Bicuspid disease and tricuspid aortic valve prolapse were associated with excessive valve mobility and eccentric jet direction and origin. Conversely, annular dilation, rheumatic disease, sclerosis, and perforation were associated with normal or reduced cusp mobility and a central jet direction and origin (p = 0.001). Overall, an eccentric jet direction occurred in 69% of patients with excessive cusp mobility, whereas 71% of patients with normal or reduced cusp mobility had a central jet (p = 0.001). Therefore color flow Doppler determination of the eccentricity of regurgitant jet direction and origin is useful in predicting the mechanism and disease of aortic valve dysfunction. These observations may suggest the presence of prolapse and thus the potential for aortic valve repair.
Adolescent↗
Experimental and numerically modeled effects of altered loading conditions on pulmonary venous flow and left atrial pressure in patients with mitral regurgitation.
Pulmonary venous flow measured by pulsed-wave Doppler transesophageal echocardiography reflects the effects of mitral regurgitation on left atrial pressure contour. To assess the relationship between pulmonary venous flow and left atrial pressure in patients with mitral regurgitation under altered loading conditions, we studied 25 patients with 3+ or 4+ mitral regurgitation and a control group by measuring pulmonary venous flow with transesophageal echocardiography and left atrial pressures after administering saline solution (n = 6), nitroglycerin (n = 6), phenylephrine (n = 6), or nitroprusside (n = 7). After administration, the left atrial pressure v wave increased in the group given phenylephrine, concomitant with an increased diastolic flow. In contrast, the left atrial pressure v wave decreased in the group given nitroglycerin, concomitant with a decreased diastolic flow. Changes in diastolic flow were closely related to changes in the left atrial pressure v wave under all loading conditions (r = 0.91; p < 0.0001). Numeric modeling of left atrial pressure and pulmonary venous diastolic flow corroborated the experimental findings. We conclude that changes in pulmonary venous diastolic flow are closely related to changes in the left atrial pressure v wave in mitral regurgitation, under altered loading conditions.
Adult↗
Muscle powered circulatory assist device for diastolic counterpulsator.
A diastolic counterpulsator that uses either skeletal muscle or pneumatic actuation was developed. The unit is positioned between the latissimus dorsi and the chest wall, without interference with collateral blood supply, and is connected in series with the descending aorta. The system was able to generate stroke volumes between 52 and 16 ccs against pressures of 60 and 140 mmHg, respectively. Stroke work at 200 msec stimulation averaged 2.8 X 10(6) ergs. Power output at an afterload of 100 mmHg, and at a rate of 60 bpm, was 0.51 W. Back-up pneumatic actuation provided by an intraaortic balloon pump resulted in a 46% increase in the endocardial viability ratio (EVR).
Animals↗
Hemisternotomy approach for aortic and mitral valve surgery.
After exploring several less invasive approaches for cardiac valve surgery, we have concluded that the partial upper sternotomy is the incision of choice for minimally invasive aortic and mitral valve surgery. From March 1997 to January 1999, 827 patients had cardiac valve surgery using this approach; 462 had mitral valve procedures and 365 had aortic valve procedures. Of those having mitral valve surgery, 87% had mitral valve repair. Aortic valve surgery included replacement with stented bioprostheses (38%), allografts (29%), and mechanical prostheses (10%); in addition, 23% had aortic valve repair. Operative mortality was 0.8%. Conversion to full sternotomy was necessary in 2.4%. Blood use was low with 80% of patients receiving no blood transfusions. We conclude that all primary mitral and aortic procedures can be accomplished safely via partial upper sternotomy.
Aortic Valve↗
A numerical model and spreadsheet interface for pumping test analysis.
Curve-matching techniques have been the standard method of aquifer test analysis for several decades. A variety of techniques provide the capability of evaluating test data from confined, unconfined, leaky aquitard, and other conditions. Each technique, however, is accompanied by a set of assumptions, and evaluation of a combination of conditions can be complicated or impossible due to intractable mathematics or nonuniqueness of the solution. Numerical modeling of pumping tests provides two major advantages: (1) the user can choose which properties to calibrate and what assumptions to make; and (2) in the calibration process the user is gaining insights into the conceptual model of the flow system and uncertainties in the analysis. Routine numerical modeling of pumping tests is now practical due to computer hardware and software advances of the last decade. The RADFLOW model and spreadsheet interface presented in this paper is an easy-to-use numerical model for estimation of aquifer properties from pumping test data. Layered conceptual models and their properties are evaluated in a trial-and-error estimation procedure. The RADFLOW model can treat most combinations of confined, unconfined, leaky aquitard, partial penetration, and borehole storage conditions. RADFLOW is especially useful in stratified aquifer systems with no identifiable lateral boundaries. It has been verified to several analytical solutions and has been applied in the Snake River Plain Aquifer to develop and test conceptual models and provide estimates of aquifer properties. Because the model assumes axially symmetrical flow, it is limited to representing multiple aquifer layers that are laterally continuous.
Environmental Monitoring↗
Central nervous system complications of coronary artery bypass graft surgery: prospective analysis of 421 patients.
A prospective analysis of 421 patients undergoing coronary artery bypass graft (CABG) surgery as the sole cardiac procedure was carried out to assess the frequency of central nervous system (CNS) complications. In all, 451 variables were assessed in each patient. Stroke occurred in 5.2% but was severe in only 2%. Prolonged encephalopathy occurred in 11.6% but usually resolved before discharge. No statistically significant pre- or intraoperative risk variables for CNS complications were found; specifically, age or pump times in excess of two hours were not significant factors. Postoperative use of an intraaortic balloon pump and pressor agents were significantly correlated with prolonged encephalopathy. The frequency of CNS injury in CABG surgery is similar to that in other forms of open heart surgery, and there has been little change in the frequency of CNS complications over the past seven years. Possible mechanisms of CNS damage during CABG surgery are discussed.
Adult↗
Incidence of postoperative delirium following myocardial revascularization. A prospective study.
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Adult↗
Coronary artery bypass graft surgery in the elderly. Indications and outcome.
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Aged↗
Mitral valvuloplasty at the Cleveland Clinic Foundation.
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Adolescent↗
The value of echocardiography in mitral valve repair.
Valve repair is the best operation currently available for patients with mitral valve disease. However, repair is technically more difficult than valve replacement and has a risk of early and late failure. Echocardiography permits better diagnosis and management of these problems. Preoperative echocardiography, including Doppler color flow mapping to evaluate intracardiac flow, is used to assess the feasibility of repair. Intraoperatively, epicardial and transesophageal echocardiography are used to monitor surgical results immediately after repair, ensuring successful outcome of surgery.
Echocardiography↗
Bullectomies for bullous sarcoidosis.
A 36-year-old woman presented with respiratory insufficiency due to cystic sarcoidosis. She had been previously treated with multiple courses of prednisone without improvement. Enlarging blebs involving both lower lobes impaired the function of the relatively spared upper lobes. Bilateral lower lobectomies were performed in one step via median sternotomy without complications, with prompt subjective and objective improvement of her respiratory status. One-stage bilateral upper-lobe bullectomy for bullous emphysema has been previously reported, but to our knowledge this is the first performance of one-stage bilateral lower-lobe bullectomies for cystic sarcoidosis. The immediate benefits were evident; long-term results will depend on the course of the underlying disease.
Adult↗
Effect of guided imagery on length of stay, pain and anxiety in cardiac surgery patients.
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Anxiety↗
Optimization of pacing parameters for conditioned latissimus dorsi muscle in cardiomyoplasty.
Synchronous paced contractions of latissimus dorsi muscle pedicle (LDM) around the heart improve ventricular function in dynamic cardiomyoplasty. To optimize assistance and prolong pacemaker battery life, the LDM should be stimulated with the lowest energy pacing parameters (PP) that will produce maximal muscle contraction. Muscle fractional shortening (FS) and duration of contraction (CT) were studied in conditioned, fatigue-resistant LDM of six goats. Fractional shortening and CT were determined at increasing amplitude, (A, 1-6v); pulse width, (PW, 60-450 musec); and frequency, (F, 5-130 Hz). Maximal rate of contraction was determined by pacing at higher rates. Maximal FS plateaued after V, 2.4 +/- .6v; PW, 125 +/- 47 musec; and F, 36 +/- 9 Hz. Mean CT for all PP was significantly longer (p less than or equal to 0.001) than the burst length (185 msec). Increasing F resulted in CT, which peaked at 460 +/- 59 msec. Increasing rate of contraction demonstrated that over 87 beats per minute the muscle fails to achieve complete relaxation, and, therefore, maximal FS.
Animals↗
Nonpulsatile ventricular assist bridging to transplantation.
Six patients accepted into a cardiac transplantation program have been supported with a Biomedicus LVAD. Five of the six patients deteriorated while awaiting a donor organ; the sixth was being supported with a device following mitral valve surgery and showed no recovery of ventricular function. In all cases the device was used only after all other therapeutic modalities had failed. The periods of support ranged from 2.5 to 31 days, mean of 10 days. Three patients underwent cardiac transplantation and all three have been discharged and are well. The three survivors were supported for 2.5, 3, and 31 days. Three deaths occurred in the patients supported for 5, 9, and 15 days, the causes being sepsis, massive cerebral embolism, and respiratory failure. Patients were for the most part maintained with some degree of heparinization, and hemolysis was a significant problem in only one patient and associated with a very small arterial return cannula. Flows were routinely maintained above 2.4 L/min/m2, and all showed recovery of other organ functions while being supported. The patient supported for 31 days was capable of limited mobilization by use of the removable drive system. The Biomedicus LVAD represents a relatively inexpensive support modality for patients awaiting cardiac transplantation.
Adult↗
Enhanced cardiac performance following cardiopulmonary bypass.
Changes in cardiac performance during coronary revascularization surgery were followed in 22 selected patients with normal or mildly impaired left ventricles; vasoactive or inotropic drugs were generally avoided. Arterial pressure, filling pressures, and cardiac output were measured; stroke volume and work were calculated before induction of anesthesia, following sternotomy, soon after discontinuation of extracorporeal circulation, and one hour postoperatively. Induction and sternotomy were associated with a depressant effect on cardiac performance. After extracorporeal circulation, however, cardiac performance recovered, cardiac output increased to 7 +/- 0.5 l/min from a preoperative control of 4.9 +/- 0.3 L/min (p less than 0.002) without an elevation of atrial pressures. This increase in cardiac output after bypass resulted from decreased afterload and increased preload secondary to hemodilution. Cardiac performance approached control values early in the postoperative period.
Adult↗
Technical and economic feasibility of reusing disposable perfusion cannulae.
The reuse of disposable devices is a potential source of significant cost savings to hospitals. Venous and arterial perfusion cannulae under new and reused conditions were selected to identify the clinical, safety, technical, logistic, and economic issues that must be addressed to realize these savings. Single- and dual-stage venous and arterial cannulae from two manufacturers were tested when new, after initial clinical use, and after a single clinical use plus up to nine simulated reuses. Reuse was simulated by end-to-end bending, coupling and uncoupling the connectors, and by two 1-hour soaks in plasma at 4 degrees C and 40 degrees C, respectively. Cannulae were decontaminated and then sterilized by a peracetic acid based liquid chemical sterilization system following each use/reuse. Sterilization was validated by eliminating Bacillus subtilis spores from the cannulae on each of five consecutive cycles. Cannulae were tested for physical changes, functional integrity, biocompatibility, and in vivo performance in sheep. A cost minimization analysis was also performed. No clinically important differences were found between new and reused cannulae, even after nine simulated reuses. Mechanical changes were less than 20% on all variables studied and were undetectable by experienced cardiac surgeons in selective evaluation. Sterilization was successfully achieved. Reusing cannulae for times would reduce the cost per procedure from $53 to $19 (64%). Perfusion cannulae tested can be safely and efficaciously used five times. This study suggests that reuse would result in a small incremental savings; however, with more expensive devices and higher-volume sterilization procedures, the savings could be exponentially greater. Although this study demonstrates that it may be technically feasible and cost-effective to reuse disposable cannulae, the U.S. Food and Drug Administration does not sanction the reuse of disposable cannulae.
Animals↗