Search PubMed⌕ Search

Biomedical subjects

D G Pennington

Publications and source records attributed to D G Pennington.

At least 73 records · Page 4Linked to original sources
PubMed1991

The free transverse rectus abdominis myocutaneous flap in breast reconstruction after mastectomy.

Breast reconstruction after mastectomy by the transverse rectus abdominis myocutaneous (TRAM) flap technique is a widely accepted method which allows reconstruction without the need for an implanted silicone prosthesis. Even in suitable patients, deficiencies of the traditional technique, where the blood supply is based on anastomotic vessels in the superior part of the rectus abdominis muscle, may lead to complications. These include flap failure, fat necrosis which may mimic recurrence of breast carcinoma or sub-optimal cosmetic results. By transferring the same abdominal tissue as a free flap based on the inferior epigastric vessels, a more reliable blood supply and better cosmetic results can be obtained. This article reports a series of 14 flaps in 13 patients in whom an entirely free flap technique was used. No flap losses were recorded and the results are judged to be superior to the traditional technique.

Abdominal Muscles↗
PubMed1991

Surveillance for rejection by echocardiographically guided endomyocardial biopsy in the infant heart transplant recipient.

Echocardiographically guided endomyocardial biopsy via percutaneous right internal jugular vein puncture has been performed 98 times in six patients 5-16 years of age at our institutions. The use of this approach was extended for rejection surveillance in seven infants transplanted at 2 weeks to 15 months of age (median, 2 months; mode, 2 weeks). A total of 35 consecutive biopsies were performed under heavy sedation in these infants (lowest weight, 3.0 kg) with the use of a 5F semirigid bioptome through a 5.0-cm 5F sheath. There was no case of entrance failure. A median of four biopsies was performed on each child (range, one to 14). Four to seven tissue pieces per biopsy were obtained using an apical four-chamber view for bioptome guidance. Ten instances of clinically suspected rejection were not confirmed by biopsy, and two cases of unsuspected rejection were found. The only complication was one instance of new mild tricuspid regurgitation in this group compared with one instance of increased tricuspid regurgitation after biopsy in the older child group. These preliminary results suggest that echocardiographically guided endomyocardial biopsy from the right internal jugular approach is a reliable and safe means for rejection surveillance in the infant and young child.

Biopsy↗
PubMed1991

Detection of lung rejection with indium-111-labeled lymphocytes in heterotopic rat heart-lung transplantation.

To determine if acute lung rejection after heart-lung transplantation can be detected noninvasively with indium-111-labeled (111In) lymphocytes, we studied 33 allogeneic and 18 isogeneic heterotopic heart-lung transplants in rats. Twenty-four hours after injection of isogeneic splenic 111In-lymphocytes (75 +/- 2 microCi/100 million cells), animals were scanned at 2 to 8 days after transplant (Tx). Also, percent indium uptake of the graft was determined and compared with pathologic lung changes. Between the vascular and destructive phases of lung rejection, 111In-lymphocyte uptake of lung allografts was significantly greater than isografts (p less than 0.001). Lung allografts in the alveolar phase (4-6 days after Tx) showed the most intense uptake (2.7 +/- 0.1%) of injected 111In-lymphocytes. All scintigrams of allografts from the late vascular to the early destructive phase (3-7 days after Tx) showed visualization of the lung graft (27/27 true positive, sensitivity = 100%). In contrast, lung isografts of the same period showed no pathological sign of rejection and were only rarely visualized (12/14 true negative, specificity = 86%). Lung rejection may be accurately assessed noninvasively by gamma scintigraphy with 111In-lymphocytes. This technique may prove useful in the detection of acute lung rejection in human heart-lung transplant recipients. Modification of the labeling dose chosen may further improve scan accuracy.

Abdomen↗
PubMed1990

Myocardial preservation using lidocaine blood cardioplegia.

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.

Aged↗
PubMed1990

Reoperation in the intensive care unit.

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.

Adult↗
PubMed1990

Cardiac surgery in the octogenarian.

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)

Aged↗
PubMed1990

Hemodynamic predictors for weaning patients from ventricular assist devices (VADs).

In order to find hemodynamic parameters that can accurately predict whether patients can be successfully weaned from ventricular assist devices (VADs), we studied data from 17 patients supported with Pierce-Donachy VADs [11 left VAD (LVAD); 6 right VAD (RVAD)] following cardiogenic shock for periods from 1.3 to 22 days (mean 5.4). Myocardial recovery was determined by daily measurements of "pump on pump off" parameters, and the data from the 8 LVAD patients and 3 RVAD patients whose hearts recovered were compared to the data from those whose did not. In this study, daily pump on pump off hemodynamic measurements were found to be predictive of success for weaning patients from VADs. In particular, the most significant predictors were: increases in mixed venous oxygen saturation, cardiac index, mean arterial pressure and ventricular ejection fraction, as well as decreases in atrial pressures. An index for measuring hemodynamic function with the VAD off is proposed, as are models of recovery. Seventy percent of the patients weaned from VADs survived, indicating that patients appropriately weaned from VAD support have a reasonable chance for survival.

Equipment Design↗
PubMed1990

Mechanical cardiopulmonary support for refractory cardiogenic shock.

From February 1982 to February 1990, 38 patients (30 male patients and 8 female patients) ranging in age from 10 to 78 years (mean 49.4 years) have been supported with arteriovenous extracorporeal membrane oxygenation (ECMO) at St. Louis University Medical Center as a resuscitative system for cardiac arrest or cardiogenic shock. All patients were unresponsive to conventional resuscitative measures including an intraaortic balloon pump in 25 patients. Patients were resuscitated in the intensive care unit, cardiac catheterization laboratory, or the emergency department. Diagnosis varied from acute myocardial infarctions (12 patients), ischemic disease (15 patients), end-stage cardiomyopathy (7 patients), congenital heart disease (3 patients), or postoperative cardiac transplant graft rejection (1 patient). Three patients could not be resuscitated with ECMO because of low flow, but the remaining 35 (92%) achieved hemodynamic stability with ECMO flows greater than 2 L/min/m2. Duration of support ranged from 0.5 to 130 hours (mean 28 hours). Twenty-four patients were successfully weaned from ECMO support after coronary artery bypass (five patients), cardiac transplantation (two patients), or ventricular assist device insertion (eight patients), or with inotropic support (nine patients). Of the 14 patients not weaned, three were inadequately resuscitated, two had percutaneous transluminal coronary angioplasty while receiving ECMO, and nine were not candidates for further intervention. Nine (24%) patients were discharged and are long-term survivors. Our results indicate that resuscitative ECMO is useful for intervals of 12 to 24 hours and can best be applied with (1) patients younger than 60 years of age; (2) patients having acute events (failed percutaneous transluminal coronary angioplasty) amenable to surgical intervention; and (3) candidates for cardiac transplantation who could be switched to more sophisticated devices within 12 to 24 hours of ECMO insertion. With these criteria, ECMO, when used as a resuscitative system, can result in increased survival in selected patients with refractory cardiogenic shock or cardiac arrest.

Acute Kidney Injury↗
PubMed1990

Aortic valve decalcification.

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.

Aged↗
PubMed1989

Exercise capacity during the first year after cardiac transplantation.

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.

Adult↗
PubMed1989

Emergency coronary artery bypass grafting for failed angioplasty: risk factors and outcome.

It has been suggested that coronary artery bypass grafting (CABG) performed in the setting of emergent failure of percutaneous transluminal coronary angioplasty causes minimal increased risk compared with routine CABG. We reviewed the records of 103 patients undergoing emergency CABG for failed percutaneous transluminal coronary angioplasty (group 1) and compared them with an identical number of consecutive CABG patients from 1987 (group 2). Group 1 had a lower risk profile evidenced by lower mean age (p less than 0.01), fewer diseased vessels (p less than 0.0001), better ventricular function (p less than 0.001), fewer left main lesions (p less than 0.0001), and fewer patients with acute ischemia requiring intravenous administration of nitroglycerin (p less than 0.01). Despite these differences, the group 1 patients had a higher mortality rate (11% versus 1%; p less than 0.01) and a higher rate of perioperative infarctions (new Q wave) (22% versus 6%; p less than 0.01). An analysis of risk factors was performed in the group 1 patients using 36 preoperative and operative variables. Multivariate analysis revealed that left ventricular score (p less than 0.0001), preoperative (after percutaneous transluminal coronary angioplasty) need for inotropic support (p less than 0.005), and age (p less than 0.025) were independent predictors of operative mortality. In conclusion, emergency CABG after failed percutaneous transluminal coronary angioplasty carries a significantly greater risk of operative death and perioperative infarction than elective CABG.

Angioplasty, Balloon↗
PubMed1989

Coronary sinus versus aortic root perfusion with blood cardioplegia in elective myocardial revascularization.

The role of retrograde coronary sinus cardioplegia in patients undergoing elective coronary artery bypass grafting has not been fully defined. Forty patients undergoing coronary artery bypass grafting received either aortic root (20 patients) or coronary sinus (20 patients) cold potassium blood cardioplegia. The patients were similar with respect to age, ventricular function, severity of coronary artery disease, cross-clamp time, completeness of revascularization, frequency of internal mammary artery grafting, and mean infusate volume and temperature. The time required to deliver the initial dose of cardioplegic solution and the time to achieve arrest were prolonged in the coronary sinus group (p less than 0.001 and p less than 0.02, respectively). There were no differences between the two groups postoperatively with regard to enzymatic indices, hemodynamic measurement, or clinical outcome. Right ventricular function was preserved equally in both groups. We conclude that coronary sinus cardioplegia is a safe alternative to aortic root perfusion, but offers no advantage in elective myocardial revascularization.

Aged↗
PubMed1989

Valve replacement in the octogenarian.

Twenty-five patients (11 men and 14 women) aged 80 to 88 years (mean age, 82 years) underwent valve replacement at St. Louis University from August 1980 to June 1988. Isolated valve replacement was performed in 11 patients. Combined procedures included valve replacement with myocardial revascularization (7 patients), multiple valve procedures (5 patients), and ascending aortic plication (2 patients). Fifteen patients (60%) were in New York Heart Association functional class III and 10 (40%) were in class IV preoperatively. The operative mortality was 20% and late mortality was 20% (mean follow-up, 36 months). Isolated valve replacement carried a 9% early and 0% late mortality, whereas combined procedures of any type had a 16% early and 20% late mortality. Only 7 patients (28%) had a completely uncomplicated postoperative hospitalization. Twenty patients were discharged after a mean hospital stay of 18 +/- 16 days. Their mean New York Heart Association functional class was 1.6 +/- 0.66. The 1-year and 2-year actuarial survival rate is 79% and 69%, respectively. A significant increase in operative mortality is seen when valve replacement is combined with myocardial revascularization or an additional valve procedure. Late clinical improvement, as judged by return to an independent life-style, justifies this approach for select patients.

Actuarial Analysis↗