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Biomedical subjects

D C Sabiston

Publications and source records attributed to D C Sabiston.

At least 37 records · Page 2Linked to original sources
PubMed1992

Pulmonary arterial impedance after single lung transplantation.

Single lung transplantation (SLT) is emerging as definitive therapy for end-stage pulmonary disease of varying etiology, yet a complete description of the hemodynamic properties of the transplanted lung has not been reported. In this study, Fourier analysis was used to calculate the pulmonary arterial (PA) impedance spectrum before and immediately after SLT to define precisely the pulmonary pressure-flow relationship. Median sternotomies were performed in 18 dogs (donors): an ultrasonic flow probe was placed around the PA and micromanometers were placed in the PA and left atrium (LA). Control PA pressure and flow (PAQ) and LA pressure were measured during transient occlusion of the right PA. The lungs were harvested using cold modified Euro-Collins solution for preservation. After thoracotomy and pneumonectomy, left SLT was performed in 18 recipient dogs with a mean ischemic time of 179 +/- 6 min. After reperfusion for 1 hr, PA pressure and flow data were again collected. Characteristic impedance (Z0), a measure of resistance to pulsatile flow, was compared to input resistance (Rin), a measure of resistance to mean flow, and pulmonary vascular resistance (PVR), the conventional index. Rin is defined as the zeroth harmonic of the impedance spectrum and Z0 as the mean of impedance moduli from 2-12 Hz. All recipients survived transplantation. Both PVR and Rin increased significantly after transplantation (11 +/- 1 vs 19 +/- 3 Wood U, P less than 0.05, and 1352 +/- 121 vs 1964 +/- 244 dyne.sec.cm-5, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Effects of arterial hypertension on myocardial recovery after ischemic injury.

Although improved surgery, angioplasty, and thrombolysis have made early revascularization of ischemic myocardium commonplace, the effects of arterial hypertension on myocardial recovery remain unclear. Therefore eight conscious dogs were instrumented to measure left ventricular transmural pressure and myocardial segment length in the left anterior descending (LAD) coronary distribution. Reversible ischemic injury was produced by two 15-min LAD occlusions separated by 4 days of reperfusion, with each dog randomly receiving either phenylephrine or placebo infusion for 30 min beginning 1 h after reperfusion. With ischemia, systolic myocardial performance fell to 14.3 +/- 3.7% of control and required greater than 48 h to recover. Compared with placebo, phenylephrine significantly depressed recovery of systolic function assessed by systolic shortening (57 +/- 12 vs. 85 +/- 13% control) or the area under the stroke work vs. end-diastolic length relationship (62 +/- 14 vs. 93 +/- 7% control) (both P less than 0.05). These data imply that ischemically injured myocardium is highly sensitive to arterial hypertension and that ventricular loading is a major determinant of the rate of myocardial recovery.

Animals↗
PubMed1991

Origin of the left coronary artery from the pulmonary artery in older adults.

Origin of the left coronary artery from the pulmonary artery is usually a serious clinical problem; untreated, it often causes death. Usually the condition becomes symptomatic early in life, but occasionally symptoms do not manifest until later in childhood. A smaller group will not have symptoms until early adulthood. Rarely, this lesion may be asymptomatic for decades. The reports in the literature and our experience with surgical correction of this condition in patients in their sixth and seventh decades of life are described. One patient is the oldest reported in the world literature to have this condition.

Cardiopulmonary Bypass↗
PubMed1989

Utility of Doppler color flow imaging for identification of femoral arterial complications of cardiac catheterization.

Doppler color flow and two-dimensional ultrasonographic images of the femoral region were obtained in 25 patients referred for suspected vascular complications of cardiac catheterization. Five patients had normal findings, while 23 abnormalities were noted in 20 patients, including seven femoral arteriovenous fistulae, 12 femoral pseudoaneurysms, and two patients with both femoral arteriovenous fistulas and pseudoaneurysms. Operation confirmed the abnormalities diagnosed by color flow examination in 15 of 20 patients. Three patients refused operation and one was not felt to be a surgical candidate due to high anesthetic risk. One patient died preoperatively and postmortem examination confirmed the color flow diagnosis. Etiologies of the arterial complications included percutaneous aortic valvuloplasty (6), coronary angioplasty (4), and arterial or both arterial and venous catheterization (10). Doppler color flow imaging is a reliable technique for identification of vascular complications following catheterization procedures.

Aged↗
PubMed1989

The use of intraoperative echo with Doppler color flow imaging to predict outcome after repair of congenital cardiac defects.

Surgical repair of congenital cardiac defects (CCD) has undergone a remarkable evolution in the past decade. Major defects are now often completely corrected in early infancy with continually improving rates of survival. It has become clear that the next major focus will be improvements in the long-term quality of life and this has promoted many innovations in surgical technique and approach. One advance is the use of intraoperative echo with Doppler color flow imaging (echo-DCFI) to evaluate the exactness of operative repair. Aside from anecdotal reports, very little information is available regarding the interpretation of images produced by this technology in the operating room. Furthermore there have been no studies addressing the predictive value of intraoperative echo-DCFI findings with respect to outcome for patients undergoing repair of CCD. The prospective data obtained by following the course of 273 patients receiving intraoperative echo-DCFI has been reviewed after repair of a variety of CCD (age range, 1 to 53 years; mean 5.3 years; smallest patient, 1.8 kg). Forty-seven patients (17%) had initially unacceptable results, by echo, at the completion of their repair. Eighteen of these patients (7% of entire series) had no clinical problems and the defects were discernible only by echo. Twenty-six patients with initially unacceptable results had their repairs revised in the operating room and left with an acceptable result by echo. Twenty-one patients were allowed to leave the operating room with echo-discernible defects. Follow-up of these patients demonstrated a significantly higher (p less than 0.006) rate of reoperation (42% vs. 3%) and of early death (29% vs. 10%) for those patients whose defects were left unrepaired compared to those whose problems were corrected before leaving the operating room. Sixty-eight patients (25%) had some alteration of ventricular function (compared to their prebypass evaluation) at the completion of their repair. Regardless of whether the dysfunction was limited to the right ventricle, left ventricle, or was biventricular, patients in this group had a significantly higher incidence (p less than 0.004) of early, but not late, death compared to patients without alteration of ventricular function (35% vs. 4%). Patients who left the operating room with no problems of concern by echo-DCFI had a greater than 90% likelihood of a long-term acceptable outcome compared to patients who had any problem of concern (residual defect, anatomic or technical imperfection, ventricular dysfunction, and so on) whose long-term likelihood of an acceptable outcome approached 50% (p less than 0.0125).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1989

The Blalock-Taussig shunt: an analysis of trends and techniques in the fourth decade.

The original description of the Blalock-Taussig shunt was published in 1945 and represented the first direct surgical procedure for the treatment of cyanotic congenital heart disease. The present study analyzes the results of Blalock-Taussig shunts performed at Duke University Medical Center during the fourth decade since the original description of the procedure. From 1975 to 1984, 53 classic and 24 modified Blalock-Taussig shunts were performed with a hospital mortality of 8%. These deaths occurred in critically ill patients with either pulmonary atresia or complex congenital cardiac lesions. The results of the early group (1975-1979) were compared to the late group (1980-1984) of patients. There was a greater proportion of infants less than 1 week of age in the late group, and the actuarial event-free shunt survival following operation was significantly better in the late group. This improvement in the late group was apparent both in patients receiving classic and modified Blalock-Taussig shunts and probably represents the effects of advances in microsurgical technique as well as improvement in the support of critically ill infants at the time of surgery by pediatric anesthesiologists and neonatologists. The data in the present study indicate that the mortality associated with Blalock-Taussig shunting is related to the condition of the patient at the time of surgery and the underlying cardiac pathology rather than the age of the patient at the time of shunting. The efforts to further reduce morbidity and mortality associated with Blalock-Taussig shunting should therefore be directed primarily to the support of infants during the preoperative and intraoperative phases of care.

Actuarial Analysis↗
PubMed1989

Intraoperative prebypass and postbypass epicardial color flow imaging in the repair of atrioventricular septal defects.

The use of intraoperative epicardial Doppler echocardiography with color flow imaging both before and after cardiopulmonary bypass to assist repair of congenital heart defects in infants and small children has not been reported. To demonstrate its simplicity and utility, we obtained immediately prebypass and postbypass examinations from 18 consecutive patients undergoing repair of atrioventricular septal defects between March 1987 and March 1988 (aged newborn to 3 years, smallest 2.4 kg, 11 patients less than 1 year old). Direct application of a sterile transducer to the epicardial surface eliminates any restriction imposed by the transesophageal approach, and the routine use of color flow imaging enables the operating surgeon to directly evaluate intracardiac anatomy and flows in a variety of orientations. Average examination time was 3.95 +/- 1.96 minutes. Prebypass studies disclosed that a short-axis inspection through the common atrioventricular valve orifice produced a unique visualization of the dynamic commitments of atrioventricular valve tissue throughout systole and diastole that was helpful in planning valve allocation during repair. In addition, echocardiography demonstrated features not previously appreciated in seven of 18 patients (39%). In all, image quality and resolution were vastly superior to preoperative chest wall studies. Postbypass studies revealed significant residual interventricular shunts in two of 18 patients (11%). Views obtained from various orientations directed specific and efficient repair immediately so that all patients left the operating room with documented, surgically acceptable results. Comparison of ventricular function between prebypass and postbypass studies enabled appropriate application of pharmacologic agents in the operating room if necessary. All patients survived their operation. There have been two late deaths, and 16 patients are alive and doing well (follow-up: 9 to 21 months). These experiences indicate that intraoperative epicardial Doppler color flow imaging (1) can be easily learned and applied by the surgeon, (2) enhances the repair of atrioventricular septal defect by providing unique spatial, anatomic, and flow information in the beating heart at the time of repair, (3) increases confidence of a surgically acceptable repair before the patients leave the operating room, (4) guides specific surgical or anesthetic adjustments to optimize results, and (5) works as a valuable aid that may help reduce poor results in the repair of complex congenital cardiac lesions.

Abnormalities, Multiple↗
PubMed1988

Alveolar cell carcinoma of the lung: a retrospective analysis of 205 patients.

From 1970 to 1986, survival of 205 patients with alveolar cell carcinoma was retrospectively studied. Analysis examined the predictive value of presenting symptoms and diagnostic screening results for pathological Stage III or IV disease (advanced) and survival. The lesion presented as a peripheral mass in 121 patients (59%) and as an infiltrate in 84 (41%). Follow-up data were available on 199 patients (97%). Variables analyzed included indices of background or risk factors, presenting symptoms, diagnostic test results, and clinical management. Seventy-nine patients (39%) had a histological diagnosis of advanced disease by TMN staging criteria. Of the 152 deaths (74%), 117 (77%) were related to the pulmonary carcinoma. Univariate analysis associated short-term and long-term anorexia, weight loss, generalized weakness, and profound dyspnea with advanced disease and ultimately with death due to cancer. Multivariate logistic regression analyses suggested that weight loss and dyspnea disclosed independent information about the likelihood of advanced disease for this population (p less than 0.0003). Cox proportional hazard regression analyses of survival revealed a significant association between weight loss and death due to alveolar cell carcinoma after pathological stage was taken into account (p = 0.001). In this series, the 80 patients with Stage I disease had the best prognosis (5-year survival of 55%). There was no significant difference in disease-free survival between patients having wedge resection (N = 17) and those having lobectomy (N = 63) for Stage I disease.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1987

Primary cysts and neoplasms of the mediastinum: recent changes in clinical presentation, methods of diagnosis, management, and results.

Major changes have recently occurred in the clinical presentation, diagnosis, and management of primary lesions of the mediastinum. New diagnostic techniques and improved therapy have led to more objective preoperative diagnoses as well as better long-term results. These features are clearly demonstrated in a series of 400 consecutive patients with primary lesions of the mediastinum seen at Duke University Medical Center. Of these, 99 (25%) had a primary cystic lesion. The primary tumors included thymic neoplasms (17%), neurogenic tumors (14%), lymphoma (16%), germ cell tumors (11%), and a miscellaneous group. Malignant neoplasms were present in 166 patients (42%). The anterosuperior mediastinum was the most commonly involved site of a primary cyst or neoplasm (54%), followed by the posterior mediastinum (26%) and the middle mediastinum (20%). Symptoms were present in 62% of the patients and included chest pain (30%), dyspnea (16%), fever and chills (20%), and cough (16%). Of the lesions found on routine chest roentgenograms, 83% were benign. In contrast, 57% of the lesions in symptomatic patients were malignant. Prior to 1967, 94% of asymptomatic lesions were benign, but this figure has now decreased to 76%. Fifty percent of symptomatic patients had a malignant neoplasm before 1967 compared with 62% after that year. Newer diagnostic techniques have greatly enhanced the accuracy of the preoperative diagnosis. They include radioisotopic scanning, monoclonal antibodies, hormonal assay, electron microscopy, fine-needle aspiration biopsy, computed tomographic scans, and magnetic resonance imaging. Each has a definite role and is specifically illustrated as being quite important in this series.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1987

Origin of the right pulmonary artery from the ascending aorta.

Origin of the right pulmonary artery from the aorta is a congenital malformation usually associated with serious symptoms in the first year of life and characterized by a poor prognosis. Sixty-five patients with this disorder have been reviewed in the literature, and 95% presented during the first year with signs of congestive heart failure. All had cardiomegaly by radiographic and electrocardiographic examination. An accurate diagnosis was established by cineangiography, and associated cardiovascular anomalies were present in 85%. Origin of the right pulmonary artery from the ascending aorta is much more common than origin of the left pulmonary artery from this vessel (8 to 1). Twenty-three patients were managed without operation with a 30% 1-year survival rate. Among those patients managed surgically, the survival rate was 84% at 1 year. It is now clear that operation should be done as early as possible to prevent irreversible changes occurring in the pulmonary arterial vasculature since microscopic features of pulmonary hypertension have been seen during the first month of life. One patient was operated on at 5 months with correction of the deformity. The pulmonary arterial pressure decreased to normal after operation. This child is now asymptomatic and his 10-year postoperative follow-up is the longest found in the literature.

Age Factors↗
PubMed1986

Utility of echocardiography in the management of patients with penetrating missile wounds of the heart.

Nine consecutive patients with penetrating missile wounds of the heart were evaluated by M-mode and two-dimensional echocardiography for localization of retained missile fragments noted to be moving in synchrony with the heart by fluoroscopy. Echocardiography precisely located all 12 moving fragments: 2 in the pericardium, 5 in the anterior right ventricular wall, 3 in the free left ventricular wall, 1 in the interventricular septum and 1 in the right posterior atrioventricular groove. Five patients had echocardiographic evidence of pericardial effusion and only one manifested a wall motion abnormality, indicating that direct myocardial perforation does not always result in detectable intrapericardial bleeding or asynergy. Localization of the missile fragments to be in danger of endocardial perforation, in danger of eroding the right coronary artery and creating a clinically unsuspected membranous ventricular septal defect led directly to surgical intervention in three different patients. In all three, intraoperative echocardiography quickly localized the missile fragments and significantly reduced patient cardiopulmonary bypass time. In the remaining six patients, localization of missile fragments well within the myocardium with no danger of erosion led to decisions against surgical removal.

Adolescent↗
PubMed1986

Management of benign and malignant lesions of the trachea and bronchi with the neodymium-yttrium-aluminum-garnet laser.

Fifty patients with lesions of the trachea or bronchi have been treated with the neodymium-yttrium-aluminum-garnet laser. Forty-three patients had advanced carcinoma of the lung with pulmonary infection or abscess distal to an obstructing bronchial lesion or else had hemoptysis. Benign lesions were seen in seven patients. A total of 72 laser treatments were administered for obstruction and/or hemoptysis. There was no significant morbidity and only one hospital death occurred, which was unrelated to the laser therapy. Among the 43 patients with malignant disease, obstructive complications and hemoptysis were controlled in 39. All those with benign lesions have been significantly improved. Presently 22 patients with malignant disease remain alive and are symptomatically improved. The longest survival after successful laser treatment has been 73 weeks, and 34 survived longer than eight weeks. This laser is a very effective means of managing patients with benign lesions and offers significant palliation for patients with hemoptysis and advanced obstructing carcinoma of the trachea or main-stem bronchus.

Adult↗
PubMed1986

Clinical and angiographic assessment of complex mammary artery bypass grafting.

The internal mammary artery has become the coronary bypass graft of choice in recent years because of enhanced long-term patency. Along with this trend, sequential, bilateral, and free mammary grafts have been employed more frequently in an effort to maximize the number of distal internal mammary anastomoses. This approach of maximally using the internal mammary artery (complex mammary grafting) seems logical, but at present little information about patency of the newer types of internal mammary artery grafts is available to justify the more complicated procedures. Over a 15 month period, 207 patients underwent bypass graft angiography from 1 to 32 weeks after operation. This is an 85% restudy rate for a consecutive series of coronary bypass procedures. Patency was defined as complete filling of the graft and distal vessel bypassed. A total of 841 distal vessels were grafted, or 4.1 per patient. The overall patency rate was 91% for 503 distal vein graft anastomoses and 99% for 338 internal mammary artery grafts. Individual patency rates of distal anastomoses, expressed as number patent/total (percent patent), were as follows: simple vein grafts, 262/285 (92%); sequential vein grafts, 196/218 (90%); left internal mammary artery to left anterior descending coronary artery, 109/110 (99%); left internal mammary to circumflex marginal artery, 14/14 (100%); right internal mammary to right coronary artery, 19/20 (95%); right internal mammary to left anterior descending coronary artery, 10/10 (100%); right internal mammary to circumflex marginal artery via transverse sinus, 18/20 (90%); sequential left internal mammary artery to left anterior descending system, 133/134 (99%); sequential left internal mammary to circumflex marginal system, 15/15 (100%); free internal mammary artery, 9/9 (100%); free sequential internal mammary artery, 6/6 (100%). Of the 18 patent transverse sinus right internal mammary grafts to the circumflex marginal artery, three exhibited very slow flow and probably were not functional. The hospital mortality associated with internal mammary revascularizations was 0.4% for nonemergency cases and 3.1% for emergency procedures. On the basis of clinical and postoperative graft patency data, expanded use of more complicated types of mammary grafts seems justified. Function of the right internal mammary graft to the circumflex marginal artery was suboptimal, and this method has been discontinued. All other complex mammary techniques had excellent patency rates as compared to vein grafts, and these differences may become even more significant in the late postoperative period.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗