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Biomedical subjects

T M Sundt

Publications and source records attributed to T M Sundt.

At least 37 records · Page 2Linked to original sources
PubMed1999

Total arterial revascularization with an internal thoracic artery and radial artery T graft.

BACKGROUND: Proximal anastomosis of the radial artery to the side of the internal thoracic artery (ITA) permits complete arterial revascularization in most patients, with the aim of improving long-term results of coronary artery bypass through greater long-term graft patency. The short-term results, however, have yet to be defined. We therefore reviewed our early experience with this grafting strategy. METHODS: Between October 1, 1993, and September 1, 1998, 649 patients aged 30 to 85 years (mean, 60+/-10 years) had primary coronary artery bypass using an ITA and radial artery in a T-graft configuration. Left ventricular function was severely depressed (ejection fraction <35%) in 12%, and left main stenosis was present in 14%. RESULTS: A total of 937 distal anastomoses were performed with the left ITA (1.4 per patient) and 1,452 with the radial artery (2.2 per patient). There was one perioperative death (0.2%). There were 32 (5%) q-wave myocardial infarctions, and 14 patients (2%) had transient low output syndrome. There was one episode of hypoperfusion corrected by lengthening the left ITA. Angiography for clinical indications in 27 patients 1 to 35 months postoperatively (mean, 9.5+/-8.3 months) demonstrated a distal anastomotic patency of 100% for ITA and 82% for radial artery grafts. CONCLUSIONS: Complete arterial revascularization can be achieved with an ITA and radial artery T-graft with low operative risk and acceptable early patency. These results support the continued investigation of this grafting strategy.

Adult↗
PubMed1999

Reappraisal of coronary endarterectomy for the treatment of diffuse coronary artery disease.

BACKGROUND: The development of new technologies such as transmyocardial laser revascularization and, more recently, local delivery of angiogenic growth factors has refocused attention on the surgical management of diffuse coronary artery disease. In some cases, coronary endarterectomy is also technically feasible. To facilitate decision-making among these options, we reviewed our experience with coronary endarterectomy to determine the results to be expected with this more traditional approach. METHODS: A search of our computerized database identified 7,096 patients undergoing myocardial revascularization between January 1, 1986 and March 30, 1997, of whom 177 (2.3%) underwent endarterectomy of at least one coronary artery. Perioperative events were derived from the database. Follow-up information was obtained from patients at 3 months to 11.5 years (mean = 55.7 +/- 38.8 months) after surgery. RESULTS: Endarterectomy was performed on the right coronary artery (RCA) system in 100 patients, the left anterior descending (LAD) system in 52, the circumflex system in 18, and in multiple distributions in 7. The 30-day mortality was 7% for RCA, 0% for LAD, 17% for circumflex, and 14% for multi-system endarterectomy (p = 0.20). There were no statistically significant differences in perioperative myocardial infarction or ventricular dysrhythmia between these groups. Actuarial survival at 5 years was 76% for patients undergoing RCA endarterectomy and 75% for left sided (LAD or circumflex) endarterectomy (p = 0.91). At late follow-up, 74% (86/117) of survivors were angina-free, 6% (7/117) had undergone subsequent angioplasty, and 3% (4/117) had undergone subsequent surgery. CONCLUSIONS: Coronary endarterectomy can be accomplished with acceptable operative risk and good long-term results, even when applied in a highly selective manner. The results of novel therapies for diffuse coronary artery disease should be considered in the context of those achievable with more traditional approaches.

Actuarial Analysis↗
PubMed1999

Value of saphenous vein graft markers during subsequent diagnostic cardiac catheterization.

BACKGROUND: Although saphenous vein graft (SVG) markers have been available for many years, they have not been widely used in coronary artery bypass graft (CABG) surgery. This is likely due to the paucity of data regarding the utility of these markers in postsurgery cardiac catheterization. METHODS: We performed a prospective study of all post-CABG patients undergoing cardiac catheterization at Barnes-Jewish Hospital over a 6-month period to test our hypothesis that SVG markers would have a beneficial effect on these procedures. Differences in total procedure (arterial) time, time to image only the SVGs, fluoroscopy time, amount of contrast used, number of aortotomies, and number of views required were compared in patients with and without markers. RESULTS: Post-CABG patients undergoing catheterization who had markers (n = 76) required significantly less total procedure time (p = 0.007), fluoroscopy time (p = 0.02), and contrast use (p = 0.008). Even after adjusting for the numbers of SVG ostia and numbers of cine views, patients with markers still required less catheterization and fluoroscopy time (p < 0.01, p < 0.02) and time to image only the SVGs (p < 0.05) than those without markers (n = 106). CONCLUSIONS: SVG markers improve the efficiency of post-CABG catheterizations; they decrease the exposure of patients and cardiologists to ionizing radiation, and they decrease the exposure of patients to potentially toxic contrast agents. SVG markers are beneficial to the vast majority of post-CABG patients.

Cardiac Catheterization↗
PubMed1999

Neurological complications of cardiac surgery: the need for new paradigms in prevention and treatment.

Neurological injury is a devastating complication of cardiac surgery that results in a longer duration of hospitalization, increased costs, and increased likelihood of death. Such injury can affect any level of the central nervous system, and its manifestations are broad, ranging from neurocognitive dysfunction to frank stroke. Many variables have been found to be indicative or risk for perioperative neurological injury, but the predictive models are more useful for stroke risk than for neurocognitive dysfunction. Strategies aimed at reducing neurological injury during cardiac surgery have focused, for the most part, on the technical aspects of cardiopulmonary bypass. The concomitant performance of carotid endarterectomy and cardiac surgery continues to be controversial, although the management of patients with symptomatic carotid stenosis is better defined. Cerebral embolism, including atheroembolism from the ascending aorta, has an important role in the pathogenesis of neurological injury of all types. Epiaortic ultrasound imaging of the aorta is a sensitive technique for the identification of atherosclerosis of the ascending aorta at the time of surgery, which can allow it to be avoided and therefore reduce the risk for atheroembolism. Results of laboratory investigations have provided insight into the mechanisms of ischemic neuronal injury and a basis for the development of neuroprotective drugs. Neuroprotection may best be accomplished during cardiac surgery because, in contrast to nonsurgical situations, potential agents can be administered before the neurological insult occurs. Reducing the incidence of perioperative stroke will require a multidisciplinary approach that includes novel diagnostic and therapeutic strategies.

Aortic Diseases↗
PubMed1999

Echocardiographic characterization of left ventricular diastolic properties in patients presenting for the maze procedure.

The aim of this study is to characterize and compare the left ventricular (LV) diastolic filling patterns in patients with paroxysmal (PAF) versus chronic atrial fibrillation (CAF) undergoing the maze procedure and to examine their relation with the hemodynamic status. Fifty patients with PAF and 22 with CAF were studied. Hemodynamic measurements and transesophageal echocardiography (TEE) were performed after the induction of anesthesia but before surgical incision, at stable conditions. Transmitral (TMF) and pulmonary venous flow (PVF) velocities were recorded with the pulsed Doppler method. Statistical analysis between the two groups (PAF and CAF) was performed using Student's t-test and chi-squared test, with P less than .05 statistically significant. Compared with patients in the PAF group, those in the CAF group had: (1) higher pulmonary capillary wedge pressure (14 +/- 5 v 12 +/- 4 mm Hg; P < .05), (2) lower left ventricular fraction of area change (43% +/- 6% v 52% +/- 9%; P < .01), (3) slower PVF systolic wave velocity (23 +/- 10 v 35 +/- 15 cm/s; P < .05), and (4) lower ratio of PVF systolic to diastolic wave velocity (0.75 +/- 0.3 v 1.2 +/- 0.4; P < .05). In the present study, LV filling patterns of abnormal relaxation were found in all our patients who underwent the maze procedure for CAF or PAF. Although the cause of LV filling abnormalities is not apparent, the data suggest LV diastolic dysfunction is prevalent in these patients.

Adult↗
PubMed1999

Clinical experience with the holmium:YAG laser for transmyocardial laser revascularization and myocardial denervation as a mechanism.

Transmyocardial laser revascularization is emerging as a treatment option for patients with debilitating angina pectoris and no conventional treatment option. Results with the high powered CO2 laser have been reproducibly encouraging. As the mechanism of action remains uncertain, the importance of the type of laser used is unknown. Interest in developing less invasive approaches, ultimately including catheter-based technologies, has stimulated the evaluation of alternative laser energy sources with fiberoptic delivery systems. One such device is the holmium:YAG laser. Clinical experience with the holmium:YAG-based systems is still in its early stages. We review our experience with one such device and the existing literature on the subject. We also briefly describe experimental evidence that this device is capable of denervating the heart locally.

Angina Pectoris↗
PubMed1999

Results of a comprehensive infection control program for reducing surgical-site infections in coronary artery bypass surgery.

OBJECTIVE: To evaluate the efficacy of a comprehensive infection control program on the reduction of surgical-site infections (SSIs) following coronary artery bypass graft (CABG) surgery. DESIGN: Prospective cohort study. SETTING: 1,000-bed tertiary-care hospital. PATIENTS: Persons undergoing CABG with or without concomitant valve surgery from April 1991 through December 1994. INTERVENTIONS: Prospective surveillance, quarterly reporting of SSI rates, chlorhexidene showers, discontinuation of shaving, administration of antibiotic prophylaxis in the holding area, elimination of ice baths for cooling of cardioplegia solution, limitation of operating room traffic, minimization of flash sterilization, and elimination of postoperative tap-water wound bathing for 96 hours. Logistic regression models were fitted to assess infection rates over time, adjusting for severity of illness, surgeon, patient characteristics, and type of surgery. RESULTS: 2,231 procedures were performed. A reduction in infection rates was noted at all sites. The rate of deep chest infections decreased from 2.6% in 1991 to 1.6% in 1994. Over the same period, the rate of leg infections decreased from 6.8% to 2.7%, and of all SSI from 12.4% to 8.9%. The adjusted odds ratio (OR) for all SSIs for the end of 1994 compared to December 31, 1991, was 0.37 (95% confidence interval [CI95], 0.22-0.63). For deep chest and mediastinal infections, the adjusted OR comparing the same period was 0.69 (CI95, 0.28-1.71). CONCLUSIONS: We observed significant reductions in SSI rates of deep and superficial sites in CABG surgery following implementation of a comprehensive infection control program. These differences remained significant when adjusted for potential confounding covariables.

Adult↗
PubMed1999

Multiple arterial grafts and survival.

Limitations in the long-term patency of saphenous veins for bypass grafts have encouraged interest in the use of arterial conduits. The positive effect of an internal thoracic artery graft on survival has been accepted for more than a decade, but it has proven difficult to show additional benefit from additional arterial conduits; this is probably due to multiple factors, including inappropriate choice of target vessels, short follow-up, and inadequate numbers of patients. Recently, however, the positive effect of a second arterial graft was confirmed. It will probably be difficult to show a survival benefit from a third or fourth arterial graft, but we believe that complete arterial revascularization will result in improved long-term freedom from reintervention. Interest in arterial conduits for coronary artery bypass was primarily limited to the left internal thoracic artery until the mid-1980s, when enthusiasm for the use of bilateral internal thoracic arteries grew. More recently, the gastroepiploic artery, the inferior epigastric artery, and especially the radial artery have all found advocates. However, the original conduit--and the standard against which all others are compared--is the greater saphenous vein.

Anastomosis, Surgical↗
PubMed1999

A randomized clinical trial of continuous aspiration of subglottic secretions in cardiac surgery patients.

STUDY OBJECTIVES: To determine whether the application of continuous aspiration of subglottic secretions (CASS) is associated with a decreased incidence of ventilator-associated pneumonia (VAP). DESIGN: Prospective clinical trial. SETTING: Cardiothoracic ICU (CTICU) of Barnes-Jewish Hospital, St. Louis, a university-affiliated teaching hospital. PATIENTS: Three hundred forty-three patients undergoing cardiac surgery and requiring mechanical ventilation in the CTICU. INTERVENTIONS: Patients were assigned to receive either CASS, using a specially designed endotracheal tube (Hi-Lo Evac; Mallinckrodt Inc; Athlone, Ireland), or routine postoperative medical care without CASS. RESULTS: One hundred sixty patients were assigned to receive CASS, and 183 were assigned to receive routine postoperative medical care without CASS. The two groups were similar at the time of randomization with regard to demographic characteristics, surgical procedures performed, and severity of illness. Risk factors for the development of VAP were also similar during the study period for both treatment groups. VAP was seen in 8 patients (5.0%) receiving CASS and in 15 patients (8. 2%) receiving routine postoperative medical care without CASS (relative risk, 0.61%; 95% confidence interval, 0.27 to 1.40; p = 0. 238). Episodes of VAP occurred statistically later among patients receiving CASS ([mean +/- SD] 5.6 +/- 2.3 days) than among patients who did not receive CASS (2.9 +/- 1.2 days); (p = 0.006). No statistically significant differences for hospital mortality, overall duration of mechanical ventilation, lengths of stay in the hospital or CTICU, or acquired organ system derangements were found between the two treatment groups. No complications related to CASS were observed in the intervention group. CONCLUSIONS: Our findings suggest that CASS can be safely administered to patients undergoing cardiac surgery. The occurrence of VAP can be significantly delayed among patients undergoing cardiac surgery using this simple-to-apply technique.

Cardiac Surgical Procedures↗
PubMed1998

Nontransmural laser treatment incompletely denervates canine myocardium.

BACKGROUND: Clinical experience with transmyocardial laser revascularization (TMLR) has reproducibly demonstrated an improvement in angina class. Denervation has been implicated as a mechanism whereby this clinical effect may be achieved. Because endovascular techniques for TMLR are currently under development, we investigated the impact of nontransmural endoventricular laser treatment on cardiac nerves in a canine model. METHODS AND RESULTS: Five mongrel dogs underwent creation of nontransmural endoventricular channels in the anterior left ventricle with a Holmium:YAG laser. Cardiac afferent nerve function was assessed in control and treatment regions by the epicardial application of bradykinin, a potent algesic, at initial thoracotomy before laser treatment, and at repeat thoracotomy 2 weeks later. The resulting central nervous system-mediated decrease in systemic mean arterial pressure seen in all animals at baseline was reduced by 90% at 2 weeks in the laser-treated territory but was preserved in controls. Immunoblot analysis of tissue samples taken from laser-treated regions demonstrated a 66% reduction in tyrosine hydroxylase, a sympathetic nerve-specific enzyme, as assessed by densitometry. Enzyme content was unchanged in control regions. CONCLUSIONS: These data suggest that nontransmural endoventricular laser treatment only partially denervates the heart. This may have implications for the clinical efficacy of the endovascular approach in the relief of angina pectoris.

Afferent Pathways↗
PubMed1998

Intraabdominal hemorrhage during combined coronary artery bypass and carotid endarterectomy.

Intraabdominal complications during cardiopulmonary bypass are extremely rare, with an incidence of less than 1% in multiple retrospective studies. These complications are associated with a high mortality, and their rapid diagnosis is critical to the outcome of the patient. We present a case of spontaneous intraabdominal hemorrhage after combined carotid endarterectomy and four-vessel coronary artery bypass grafting, which was diagnosed through a diaphragmatic window.

Coronary Artery Bypass↗
PubMed1997

Previous coronary artery bypass grafting is not a risk factor for aortic valve replacement.

BACKGROUND: The risk of aortic valve replacement (AVR) after previous coronary artery bypass grafting (CABG) is controversial. Its magnitude influences the threshold for recommending this procedure and has been cited in arguments regarding the optimal management of mild aortic stenosis at primary CABG. We therefore reviewed our experience with reoperative AVR +/- CABG and the primary combined procedure. METHODS: Between January 1, 1985, and June 30, 1996, 427 patients underwent primary AVR+CABG, and 52 underwent AVR +/- CABG after prior CABG. Demographics, operative characteristics, and operative results were compared between groups. Data for all patients were pooled and analyzed collectively for risk factors influencing mortality. RESULTS: The extent of native coronary artery disease and the incidence of prior myocardial infarction and stroke were greater in the reoperative group. Aortic cross-clamp and cardiopulmonary bypass times were slightly shorter, and fewer distal anastomoses were performed in the reoperative group. Operative mortality (primary group, 6.3% versus reoperative group, 7.4%) and morbidity were similar. Stepwise multivariate logistic regression analysis identified age, perioperative myocardial infarction, intraaortic balloon support, ventricular arrhythmia, perioperative stroke, and development of renal failure or acute respiratory distress syndrome, but not reoperative status, as predictors of mortality. CONCLUSIONS: The risk of AVR after previous CABG is similar to that for primary AVR+CABG. Valve replacement should, therefore, be pursued despite prior CABG when hemodynamically significant aortic stenosis develops. Furthermore, a circumspect approach to "prophylactic" AVR for mild aortic stenosis at primary CABG seems warranted.

Age Factors↗
PubMed1997

Pulmonary embolectomy after single-lung transplantation.

Single-lung transplantation for pulmonary hypertension results in a significant ventilation/perfusion mismatch with dramatic shift of blood flow, but not ventilation, to the replacement organ. This raises concern that the patient may be precariously dependent on the function of the transplanted lung. We report the successful management of a massive central pulmonary embolus to the transplanted lung in a 43-year-old woman 4 years after single-lung transplantation for primary pulmonary hypertension.

Adult↗
PubMed1997

Coronary artery bypass grafting after a bilateral lung volume reduction operation.

A 67-year-old man underwent coronary artery bypass grafting 31/2 months after a bilateral lung volume reduction operation for end-stage pulmonary emphysema. The principles of anesthetic management we have developed for use during volume reduction operations were applied with success in this individual and are described in detail. With the increasing application of this intervention as an alternative to lung transplantation, we anticipate further experience in the operative management of associated conditions after lung volume reduction operations.

Aged↗
PubMed1997

Transmyocardial laser treatment denervates canine myocardium.

BACKGROUND: In patients with refractory angina who are not candidates for conventional revascularization, transmyocardial laser treatment reduces angina significantly in the early postoperative period. We hypothesized that transmyocardial laser treatment damages cardiac nerve fibers that convey the pain of angina pectoris. METHODS: Left thoracotomy was performed in sixteen adult mongrel dogs. Treatment groups included animals in which a portion of the left ventricle underwent creation of transmyocardial channels with a holmium:yttrium-aluminum-garnet laser (n = 5) or chemical destruction of cardiac nerves by application of phenol to the epicardium (n = 5). Sham-operated negative control animals underwent thoracotomy and pericardiotomy alone (n = 6). Cardiac afferent nerve function was assessed by epicardial application of bradykinin, a potent algesic, before treatment and 2 weeks after the operation. The resulting central nervous system-mediated decrease in systemic mean arterial pressure was measured. Cardiac innervation of treated and untreated left ventricular myocardium was further assessed by immunoblot analysis performed with an antibody against tyrosine hydroxylase, a sympathetic nerve-specific enzyme. RESULTS: Before treatment, changes in systemic arterial pressure were seen with bradykinin stimulation in all dogs. Two weeks after treatment, no hemodynamic response was seen after stimulation of laser- or phenol-treated areas, but a normal response was seen after stimulation of untreated areas in these same animals and in negative control animals. Immunoblots demonstrated loss of tyrosine hydroxylase in regions of phenol and laser treatment. CONCLUSION: Transmyocardial laser treatment destroys cardiac nerve fibers, which may contribute to the reduced angina pectoris seen clinically.

Angina Pectoris↗