Biomedical subjects
Publications and source records attributed to L R McBride.
In this communication we describe a technique to change paracorporeal ventricular assist devices after the development of mechanical complications. This procedure is technically simple and in our experience does not require a sternotomy or cardiopulmonary bypass. Paracorporeal ventricular assist devices can be safely changed allowing continued support and survival.
To better define the merits of the bileaflet and tilting-disc valves, we prospectively randomized 102 patients (mean age, 57 years; range, 11 to 85 years) to receive either the St. Jude (n = 55) or the Medtronic-Hall (n = 47) mitral valve prosthesis between September 1986 and May 1991. The two groups were not different with respect to preoperative New York Heart Association class, incidence of mitral stenosis and insufficiency, angina score, extent of coronary artery disease, ventricular function, completeness of revascularization, or cross-clamp or bypass time. The hospital mortality (14.5% versus 10.6%, St. Jude versus Medtronic-Hall) and late mortality (7.3% versus 2.1%) were not significantly different. Follow-up was complete in 84 of 89 hospital survivors (94%) with a mean of 26 months (range, 1 to 60 months). The linearized rates of valve-related events and the 3-year actuarial survival demonstrated no significant differences between both cohorts. Comparison of the clinical outcome and echocardiographic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. These data indicate that the Medtronic-Hall and St. Jude mitral prostheses are similar with respect to their rates of valve-related complications and hemodynamic profiles. This study suggests that there is no difference between the St. Jude and Medtronic-Hall prostheses with regard to early clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.
The intraaortic balloon pump is usually the first mechanical device inserted for perioperative cardiac failure; however, little current information is available regarding short- and long-term effectiveness. From January 1983 through November 1990, 6856 adult patients underwent cardiac surgical procedures, 580 of whom (8.5%) had an intraaortic balloon inserted preoperatively (107 patients), intraoperatively (419 patients), or postoperatively (54 patients). There were 374 men and 206 women with a mean age of 63.9 years (range 19 to 88). Operations included 376 coronary artery bypass grafts, 100 mitral valve replacements (with or without bypass grafting), 70 aortic valve replacements (with or without bypass grafting), 15 double valve replacements (with or without bypass grafting), and 32 other procedures. There were 72 (12.4%) complications related to the balloon pump, of which 42 necessitated surgical intervention including thrombectomy (21), vascular repair (13), fasciotomy (2), aortic repair (1), and amputation (4). Operative mortality for patients supported by the balloon pump was 44%. Multivariate stepwise analysis of 27 parameters revealed six independent predictors of mortality: preoperative New York Heart Association class, transthoracic intraaortic balloon insertion (both p < 0.0001), preoperative administration of intravenous nitroglycerin, age, female gender, and preoperative balloon insertion (p < 0.001). Balloon-related complications were not predictive of death. Of the 326 hospital survivors, only 34 were lost to follow-up. There were 75 late deaths, the cause of which was cardiac in 41 (55%), noncardiac in 20 (27%), and unknown in 14 (19%). Actuarial survivals at 1, 5, and 9 years are 51%, 42%, and 33%. Of the 217 hospital survivors still alive and contacted, 81% were in class I (114) or II (60). These data demonstrate (1) operative mortality for patients requiring an intraaortic balloon in the perioperative period remains high, (2) perioperative risk factors can be identified, (3) complications related to the balloon pump do not affect survival, (4) operative survivors can achieve prolonged survival with excellent functional results, and (5) consideration for alternative methods of circulatory support is justified.
The role of retrograde coronary sinus cardioplegia in patients undergoing aortic valve replacement for aortic stenosis alone or in combination with myocardial revascularization has not been fully defined. Sixty-three patients undergoing elective aortic valve replacement received cold potassium blood cardioplegic solution via either the aortic root (36 patients) or the coronary sinus (27 patients). The patients were similar with respect to age, degree of aortic stenosis, ventricular function, severity of coronary artery disease, crossclamp time, completeness of revascularization, and mean volume and temperature of the infusion solution. The mean septal temperature and the release of myocardium-specific isoenzyme in the first 2 hours after crossclamp removal was higher in the retrograde group (p less than 0.008). Right and left ventricular function was preserved equally in the two groups, and volume-loading studies suggested improved diastolic performance in patients having retrograde cardioplegia. There were no differences between the two groups with respect to clinical outcome. We conclude that coronary sinus cardioplegia is as safe as aortic root perfusion for myocardial preservation in patients undergoing elective aortic valve replacement.
We investigated the effects of electrophysiologic testing of the automatic implantable cardioverter-defibrillator (AICD) on left ventricular systolic function and diastolic filling in 12 patients. Ventricular tachycardia or ventricular fibrillation was induced by programmed electrical stimulation and alternating-current, respectively. Patients were studied before and immediately after, 10 minutes after, and 1 hour after defibrillation by the AICD using M-mode, two-dimensional, and pulsed Doppler echocardiography. Immediately after defibrillation, increases were found in the peak early filling velocity (70 +/- 10 cm/sec to 84 +/- 24 cm/sec, p less than 0.01), peak early-to-atrial filling velocity ratio (1.05 +/- 0.21 to 1.29 +/- 0.26, p less than 0.005), and maximum rate of diastolic chamber enlargement (82 +/- 26 mm/sec to 102 +/- 44 mm/sec, p less than 0.05). These changes were not evident at 10 minutes and 1 hour. Cardiac output and ejection fraction were unchanged after defibrillation. Heart rate and diastolic filling time were unchanged. We conclude that electrophysiologic testing of the AICD does not impair left ventricular function in the immediate to 1-hour period after defibrillation. Left ventricular systolic function is unchanged and diastolic filling is enhanced.
Octogenarians are rarely referred for thoracic operations, presumably owing to the perceived morbidity of thoracotomy and the presumed frailty and limited life span of the 80-year-old patient. To determine if these concerns are valid, we reviewed our operative experience in 50 patients 80 years of age or older (mean age, 82.7 years; range, 80 to 91 years; 29 men, 21 women) undergoing thoracotomy between Nov 1, 1980, and May 1, 1990, for cancer (39 patients) and benign disease (11 patients). Procedures included 25 lobectomies (24 cancer, 1 abscess), 4 pneumonectomies (all cancer), 3 esophagectomies (1 perforation, 2 cancer), 3 explorations for cancer, 2 bullectomies, 12 wedge or segmental resections (5 open lung biopsies, 5 cancer, and 1 each for benign nodule and hemoptysis), and 1 thymectomy. Five patients (10%) were operated on emergently for massive hemoptysis (1), Boerhaave's syndrome (1), or rapidly progressive respiratory insufficiency (3) with an operative mortality of 80%. Mortality for elective cases was significantly lower (13%, p less than 0.01). Major complications occurred in 19 patients (38%). Univariate analysis performed to identify predictors of operative mortality demonstrated no significant relationship between operative death and patient age, sex, type of operation, diagnosis of malignancy, or the presence of either cardiac disease or chronic obstructive lung disease. Twenty-three patients are alive 2 months to 5 years after thoracotomy. Actuarial survival for the 45 elective patients was 56% and 44% at 1 and 2 years, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
A survey of cardiac transplantation in children provided data from 381 transplantations in 362 patients from 32 centers in the United States and ten international centers. The number of transplantations continues to increase, in part because of transplantations in infants with hypoplastic left heart syndrome and patients with congenital defects. The immunosuppression regimens were more uniform than in the 1985 survey, and triple therapy was most common. Actuarial survival rates were 85% at 1 month, 72% at 1 year, 64% at 3 years, and 60% at 5 years. However, these improved rates are still not equal to the survival of the overall cardiac transplant population, in part because of lower survival rates in neonates. Ventricular dysfunction and rejection, rather than infection, were the leading causes of death. Rejection and infection were the most frequent complications. Also common were hypertension (39%) and seizures (25%), whereas coronary artery disease (8%) was unusual. Functional results were excellent in 85%, and only 7% were disabled. Questions concerning growth rates and many other aspects cannot yet be answered. However, it is apparent that cardiac transplantation in the pediatric population is a very worthwhile endeavor.
The internal mammary artery (IMA) is the conduit of choice for myocardial revascularization. From 1972 to 1989, 586 patients received bilateral IMA and supplemental vein grafts. There were 506 men (86%) and 79 women (14%) with a mean age of 55.5 years (range 32-77 years). Unstable angina was present in 138 patients (24%), insulin-requiring diabetes mellitus in 83 (14%) and previous myocardial infarction (MI) in 25 (4%). Preoperative angiography demonstrated triple-vessel disease in 286 patients (49%) and double-vessel disease in the remaining 300 patients (51%). Left main coronary artery disease (stenosis greater than or equal to 50%) was present in 53 (9%). The mean left ventricular score was 7.4 with a range of 5 to 20. The mean number of grafts performed was 3.4 per patient. Hospital mortality was 3.6% (21 patients). Follow-up was done through direct patient contact, via the patient's physician or by telephone contact with the patient themselves or surviving family members. Follow-up was complete in 518 hospital survivors and ranged from 1 month to 17.5 years with a cumulative follow-up of 911 patient years. At 10 and 15 years, respectively, the actuarial freedom from MI was 78% and 72% and freedom from reoperation was 93% and 86%. Actuarial survival at 10 and 15 years was 85% and 70%, respectively. This longitudinal analysis demonstrates that bilateral IMA grafting has a low operative risk. The data suggest that utilization of two IMA grafts yield excellent freedom from recurrent symptoms and provides excellent long-term survival.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
One hundred consecutive patients who had coronary artery bypass grafting using both internal thoracic arteries (ITAs) and saphenous veins, operated on during a 3-year period between 1972 and 1975, have been compared retrospectively with a series of 100 patients operated on during the same period who had one ITA graft along with saphenous vein grafts. The two groups were similar with respect to age, sex, risk factors for coronary artery disease, angina class, extent of coronary artery disease, left ventricular function, number of coronary bypass grafts performed, and completeness of revascularization. Single ITA operative mortality was 2% and double ITA, 9% (p = NS). The mean follow-up of hospital survivors was 14.4 +/- 2.7 years; all but 7 patients had follow-up for at least 10 years. At 13 years, the actuarial patency of the right ITA was 85% and the left ITA, 82%. These data strongly suggest a survival benefit for patients with double ITA grafts among hospital survivors (74% versus 59%; p = 0.05). Patients receiving two ITA grafts had a significant freedom from subsequent myocardial infarction (75% versus 59%, p less than 0.025), recurrent angina pectoris (36% versus 27%, p less than 0.025), and subsequent total ischemic events (32% versus 18%, p less than 0.01). These data also suggest improved freedom from coronary artery interventional therapy (percutaneous transluminal coronary angioplasty and reoperation) when two ITA grafts were used. These results support the use of bilateral internal thoracic artery grafting in selected patients.
Prevention of ventricular fibrillation after aortic unclamping using lidocaine hydrochloride as an additive to cold potassium blood cardioplegia was studied prospectively in 46 patients undergoing elective myocardial revascularization. Patients were similar with respect to age, ventricular function, severity of coronary artery disease, cross-clamp time, completeness of revascularization, frequency of internal thoracic artery grafting, systemic temperature at the time of cross-clamp removal, and mean infusate volume and temperature. Patients receiving lidocaine blood cardioplegia (group 1, 23 patients) had a significant reduction in the incidence of ventricular fibrillation (22% versus 74%; p less than 0.0005) and in the mean number of cardioversion attempts required to defibrillate the heart (0.5 +/- 1.3 versus 1.9 +/- 0.97; p less than 0.0005) after cross-clamp removal compared with controls (group 2, 23 patients). There were no differences between the two groups postoperatively with regard to cardiac enzyme release, hemodynamic measurements, or clinical outcome. Patients receiving lidocaine blood cardioplegia tended to have a lower incidence of new postoperative atrial fibrillation (9% versus 26%). Ventricular function was preserved equally in both groups. We conclude that lidocaine is a safe additive to potassium blood cardioplegia and significantly reduces the incidence of ventricular fibrillation after aortic unclamping.
From July 1, 1984, through June 30, 1989, after 1,259 open heart operations, 110 patients (8.7%) underwent 162 early reoperations either in the intensive care unit (144 procedures) or in the operating room (26 procedures). Reexploration for bleeding (49 procedures) (3.9%) and intraaortic balloon removal (50 procedures) (4.0%) were the two most common procedures. Ninety percent and 96% of these procedures, respectively, were performed in the intensive care unit. Mediastinal infections occurred in 4 (6.1%) of 66 patients undergoing repeat mediastinal operations for all indications. No infection occurred after reexploration for bleeding nor did mediastinal infection occur after reoperation in the intensive care unit. Postoperative death in these 110 patients was not related to reoperation except possibly in the case of 1 patient (0.9%). Average transit time to and from the operating room for patients returned there for reoperation was 89.7 minutes. Charges for procedures performed in the operating room were at least twice as great as for those performed in the intensive care unit. This experience supports expanded use of reoperation in the intensive care unit, as it is safe, effective, economical, and convenient.
The increasing safety of cardiac surgery has led to the frequent referral of octogenarians for operation. Between 1980 and 1989, we reviewed our experience with 103 octogenarians (59 male, 44 female; mean age 82 years) to determine the surgical risk factors and outcome in the elderly population. There were 71 coronary bypasses (CABG), 11 aortic valve replacements (AVR), 11 AVR-CABG, 4 mitral valve replacements (MVR), 3 MVR-CABG and 3 AVR-MVR-CABG. Seventeen patients died during hospitalization (16.5%) including 9 CABG (13%); 1 AVR (9%), 2 AVR-CABG (18%), 2 MVR (50%), 1 MVR-CABG (33%) and 2 AVR-MVR-CABG (67%). Statistical analysis of 22 perioperative variables suggested that a preoperative intraaortic balloon, a history of congestive heart failure, mitral valve replacement, urgent operation, need for preoperative inotropic support and the number of anastomoses performed were significant or marginally significant (P less than 0.15) univariate predictors of operative mortality. Multivariate analysis revealed that the need for a preoperative intraaortic balloon (F = 13.1), history of congestive heart failure (F = 6.8), and MVR (F = 6.7) were significant (P less than 0.001) independent predictors of mortality. Postoperative complications included arrhythmias in 36 patients (35%), respiratory insufficiency in 11 (11%), reversible neurological deficit in 15 (14%), and a permanent neurological deficit in 6 patients (6%). Actuarial survival was 90% and 82% at 1 and 2 years, respectively. Seven of 86 (8%) long term survivors sustained a stroke in the follow-up interval. The mean follow-up of survivors was 23 +/- 19 months with a mean improvement in NYHA class of 1.4 (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Ultrasonic decalcification of the aortic valve was performed in 22 elderly patients with critical aortic stenosis (aortic valve areas less than 0.8 cm2) as an alternative to prosthetic valve replacement. All of the patients had symptoms. The mean New York Heart Association class was 3.3 +/- 0.9. Adequate decalcification with restoration of leaflet mobility was achieved in all patients, including seven with bicuspid aortic valves. Leaflet perforation occurred and was successfully repaired in five patients. Ten patients underwent concomitant myocardial revascularization. There were two operative deaths (9%) and three late deaths. Echocardiograms were obtained preoperatively, postoperatively, and at 6 months. The mean aortic valve area increased significantly from 0.72 +/- 0.17 to 1.42 +/- 0.31 cm2 (p less than 0.001) and the peak gradient decreased from 74 +/- 34 to 25 +/- 13 mm Hg (p less than 0.001). At 6 months the aortic valve area (1.29 +/- 0.48 cm2) and peak gradient (31 +/- 12 mm Hg) continued to be significantly better than the preoperative measurements (p less than 0.001), but the 6-month aortic valve area was slightly decreased and the gradient increased when compared with the immediate postoperative values (p less than 0.02). The prevalence of mild to moderate aortic insufficiency increased from 50% of the patients preoperatively to 87% at 6 months (p less than 0.05). Two patients subsequently required aortic valve replacement for restenosis and aortic insufficiency. Ultrasonic decalcification is effective in relieving aortic stenosis, but subsequent restenosis and insufficiency may limit its application.
Few data are available examining the influence of perioperative clinical parameters on exercise capacity after cardiac transplantation. Accordingly, 40 patients were studied by metabolic exercise testing early (1 to 3 months) and late (6 to 12 months) after cardiac transplantation. Various clinical parameters, including congestive heart failure class, length of hospital stay, age, cold ischemic time and histologic evidence of rejection were correlated with exercise capacity after transplantation. As expected, peak exercise capacity correlated inversely with both age and length of hospital stay. There was no correlation with preoperative congestive heart failure class or heart rate at rest. Interestingly, there was a statistically significant correlation between cold ischemic time and exercise capacity after transplantation. In addition, increased episodes of rejection during the first 6 months after transplantation resulted in statistically lower exercise capacity at 6 to 12 months after the operation. Thus, ischemic damage during transport of the donor organs and subclinical damage during early rejection may affect clinical status after heart transplantation and may only be apparent during increased physical demand such as exercise.