Biomedical subjects

M K Pasque

Publications and source records attributed to M K Pasque.

At least 37 records · Page 2Linked to original sources

PubMed1995

Pulmonary transplantation.

OBJECTIVE: More than 2700 lung transplants have been performed since the initial clinical success in 1983. The evolution in the techniques of lung transplantation and patient management and the effects on results are reviewed. SUMMARY BACKGROUND DATA: Improvements in donor management, lung preservation, operative techniques, immunosuppression management, infection prophylaxis and treatment, rejection surveillance, and long-term follow-up have occurred in the decade following the first clinically successful lung transplant. A wider spectrum of diseases and patients treated with lung transplant have accentuated the shortage of suitable lung donors. The organ shortage has led to the use of marginal donors and a limited experience using living, related donors. METHODS: Changes in techniques and patient selection and management are reviewed and controversial issues and problems are highlighted. RESULTS: One-year survival of greater than 90% for single-lung transplant recipients and greater than 85% for bilateral lung transplant recipients have been achieved. Complications caused by airway complications has been reduced greatly. Obliterative bronchiolitis develops in 20% to 50% of long-term survivors and is the leading cause of morbidity and mortality after the first year after transplant. CONCLUSIONS: Lung transplantation has evolved into an effective therapy for a wide variety of causes of end-stage lung disease. Wider applicability requires solutions to the problems of donor shortage and development of obliterative bronchiolitis.

Humans↗

PubMed1994

Biopsy-induced tricuspid regurgitation after cardiac transplantation.

Transvenous endomyocardial biopsy is now well-established as the gold standard for evaluation of possible rejection episodes after cardiac transplantation. From 1985 to August 1992, 1990 patients have undergone 193 cardiac transplantations at Barnes Hospital. One hundred eighty-three patients survived their initial hospitalization and serve as the study group. Their records were reviewed for the purposes of identifying those with tricuspid regurgitation as a complication of right ventricular endomyocardial biopsy. These patients have undergone a total of 2,960 biopsies for an average of 16.2 biopsies per patient. Over a mean follow-up period of 4.22 years, all patients have been evaluated with standard two-dimensional echocardiograms. Mild to moderate tricuspid regurgitation was very common, but was thought to be biopsy-induced only if severe and accompanied by flail components of the tricuspid valve. Twelve patients were identified with this entity at our institution. Of these, 5 had no symptoms and were receiving no diuretics, 3 had mild symptoms consisting of lower extremity edema and continued to receive diuretics, 2 had moderate symptoms, and 2 had right heart failure and anasarca refractory to medical therapy. Both of the severely affected patients subsequently required tricuspid valve replacement. We conclude that the tricuspid valve apparatus is at significant risk of injury during endomyocardial biopsy, that most patients will be minimally symptomatic due to tricuspid regurgitation when this injury occurs, and that when the injury is accompanied by severe symptoms, the likelihood of improvement with medical therapy is small.

Actuarial Analysis↗

PubMed1994

Predictors, frequency, and indications for cardiopulmonary bypass during lung transplantation in adults.

The records for 162 lung transplantations performed in 158 patients were reviewed with regard to the predictors for, frequency of, and indications for using cardiopulmonary bypass during the procedure. There were a total of 8 en bloc double-lung transplantations, 83 single-lung transplantations, and 71 bilateral single-lung transplantations. Bypass was used electively for all double en bloc and three of the bilateral sequential lung transplantation procedures and for 26 unilateral lung replacement procedures in patients with pulmonary hypertension. Of the remaining patients, 1 single-lung transplant recipient required bypass for correction of a surgical mishap and 18 bilateral single-lung recipients required bypass during replacement of the second lung. No preoperative predictors for the need of bypass could be identified. Among the bilateral sequential lung recipients, the use of bypass did not seem to adversely affect outcome, as expressed in terms of the time until extubation, the time spent in the intensive care unit, and the time required to reach a room air oxygen tension greater than 60 mm Hg.

Adult↗

PubMed1994

Differences in early results after single-lung transplantation. Washington University Lung Transplant Group.

Single-lung transplantation is an effective treatment for end-stage pulmonary failure caused by a variety of lung diseases. Although single-lung recipients may undergo a similar operative procedure, physiologic differences in the remaining native lung dictate differences in postoperative management and perhaps outcome. To examine these effects on the early results after single-lung transplantation, we retrospectively reviewed the course of 83 patients undergoing single-lung transplantation from September 1988 through July 1993. The cause of the lung disease was obstructive (OLD) in 43, idiopathic pulmonary fibrosis (IPF) in 16, and primary pulmonary hypertension (PPH) in 24 patients. The hospital mortality was 5% in OLD, 13% in IPF, and 8% in PPH. Gas exchange as demonstrated by alveolar-arterial oxygen gradients was worse after transplantation in patients with IPF (349 +/- 159 mm Hg) or PPH (270 +/- 171 mm Hg) compared with patients with OLD (174 +/- 105 mm Hg; p < 0.05). Mean pulmonary artery pressures were higher in patients with IPF (28 +/- 6 mm Hg) and PPH (26 +/- 7 mm Hg) compared with patients with OLD (22 +/- 5 mm Hg; p < 0.05). Peak airway pressures after transplantation were greater in patients with IPF (36 +/- 6 cm H2O) compared with patients with OLD (28 +/- 6 cm H2O; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Three-dimensional cardiac magnetic resonance imaging.

Evaluation of time-varying cardiac structure and function is challenging because of the three-dimensional (3-D) anatomy and time-varying (4-D) behavior of the heart. Historically, contrast angiography has served as the cornerstone of cardiac diagnosis because of its excellent spatial and temporal resolution. However, magnetic resonance (MR) imaging is now increasingly applied because of the wide variety of available MR imaging and data acquisition techniques, including spin-echo, gradient-echo, wall motion techniques, 1H 31P spectroscopy, and, most recently, echo-planar imaging. Planar 2-D MR imaging is used to characterize many aspects of cardiac structure and function, including anatomic relationships, valvular heart disease, ischemic heart disease, and congenital abnormalities, among others. The development of imaging display and data postprocessing analysis techniques have paralleled the growth of these image and data acquisition schemes and, increasingly, an emphasis has been placed on defining structure and function in 3-D, or even 4-D. Three-dimensional reconstructions of the heart have commonly relied on conventional planar MR image acquisition techniques; a 3-D volume of data is then created from stacked 2-D images. Surface reconstruction and graphical rendering techniques are used to generate representations of the heart that depict 3-D and 4-D cardiac structure and function. These techniques have been used both clinically and experimentally in a variety of settings, including ischemic heart disease, MR coronary angiography, and congenital heart disease.

Equipment Design↗

PubMed1992

Pulmonary "twinning" procedure: use of lungs from one donor for single-lung transplantation in two recipients.

Since the introduction of lung transplantation as an option for patients with end-stage respiratory disease in the early 1980s, there have been substantial advances made in the technical aspects of transplantation as well as the early clinical results. With an ever-increasing number of patients being designated suitable candidates for transplantation, the volume of transplants in the foreseeable future will be limited more on the basis of donor lung supply than any other single factor. Pulmonary "twinning" provides an important step in ensuring that all suitable and available donor lungs are utilized whenever feasible. This report reviews the results of 20 single-lung transplantations carried out in five separate transplantation centers using organs retrieved from ten donors. The overall mortality rate in this group of patients was 5%, which compares very favorably with historical controls. No serious problem was noted with respect to increased perioperative morbidity or increased ischemic times in this group of patients. We suggest that this process should be considered and, wherever possible, adopted by all major lung transplant centers.

Adult↗

PubMed1992

Management of dysfunction in the transplanted lung: experience with 7 clinical cases. Washington University Lung Transplant Group.

In a series of 34 lung transplant patients, donor lung dysfunction occurred on 7 occasions. One patient underwent retransplantation and the remaining 6 were treated conservatively. Survival was 100% in the donor lung dysfunction group. Percent predicted forced expiratory volume in 1 second, carbon monoxide diffusion, room air oxygen tension, and distance walked in 6 minutes were all lower (p less than 0.05) at 1 month after transplantation in those patients with donor lung dysfunction as compared with those without. These differences were not significant at 3 months after transplantation. We conclude that donor lung dysfunction can usually be managed conservatively with satisfactory results. Longer follow-up of this group of patients will be necessary to determine the long-term consequences of early graft injury.

Adult↗

PubMed1992

Intraaortic balloon counterpulsation: patterns of usage and outcome in cardiac surgery patients.

Between January 1, 1986, and May 6, 1991, 7,884 cardiac surgical procedures requiring cardiopulmonary bypass were performed at our institution, including 672 (9.8% of adult procedures) performed in 669 patients that were associated with preoperative (n = 240), intraoperative (n = 353), or postoperative (n = 79) use of an intraaortic balloon pump. The mean age of recipients was 65.3 years (range, 16 to 89 years). Intraaortic balloon pump usage increased during the study period from 6.4% of patients (83/1,298) in 1986 to 12.7% of patients (169/1,333) in 1990. The relative distribution between preoperative (mean, 35.7%), intraoperative (52.5%), and postoperative (11.8%) insertion remained nearly constant during the study period. The overall operative (30-day) mortality for patients with preoperative, intraoperative, or postoperative insertion of the intraaortic balloon pump was 19.6%, 32.3%, and 40.5%, respectively (X2 = 16.4; p less than 0.001). Although use of the intraaortic balloon pump in the intraoperative and postoperative settings is accompanied by a favorable outcome in most patients, the high associated mortality suggests the need for earlier use of the intraaortic balloon pump or other supportive measures such as the ventricular assist device.

Angina, Unstable↗

PubMed1992

Pressure-gated acquisition of cardiac MR images.

Electrocardiographically gated magnetic resonance (MR) image acquisition is not optimal for the quantification of in vivo cardiac deformation, because of the cycle-length dependence of cardiac mechanical events. The authors developed a method for acquisition of cardiac MR images gated to the first derivative of left-ventricular-developed pressure and used the method in a canine model. Application of this method may improve myocardial stress-strain analyses.

Animals↗

PubMed1992

Lung transplantation of ventilator-dependent patients. The Washington University Lung Transplantation Group.

During the last few years, lung transplantation has been extended to patients with a variety of end-stage lung diseases, but recipient selection guidelines have remained relatively strict. Ventilator-dependent patients have traditionally been considered poor candidates for transplantation. However, patients who have been thoroughly evaluated and accepted for transplantation and subsequently develop respiratory failure caused by progression and/or exacerbation of their underlying disease and recipients who experience respiratory failure caused by graft failure may be suitable candidates while ventilator-dependent if no other major complications or contraindications arise before a donor organ becomes available.

Adult↗

PubMed1992

The role of transbronchial lung biopsy in the treatment of lung transplant recipients. An analysis of 200 consecutive procedures.

STUDY OBJECTIVE: The purposes of this study were as follows: (1) to establish the positivity rate and complication rate of transbronchial lung biopsies in the treatment of lung transplant recipients; (2) to determine the sensitivity of transbronchial lung biopsy specimens for the diagnosis of clinically suspected acute rejection and cytomegalovirus pneumonia; and (3) to examine the results of surveillance transbronchial lung biopsies in clinically and physiologically stable recipients. DESIGN: Retrospective review and analysis of 203 consecutive procedures. SETTING: Washington University Lung Transplantation Program, Washington University School of Medicine and Barnes Hospital, St. Louis, Mo. PATIENTS: Fifty-five lung transplant recipients. INTERVENTIONS: Biopsies were done with 2-mm fenestrated forceps using fluoroscopic guidance. Two hundred three bronchoscopies with transbronchial lung biopsy were performed for clinical indications (n = 88), routine surveillance (n = 90), or follow-up of a previous biopsy (n = 25). Biopsy specimens showing acute allograft rejection were classified according to the scheme recommended by the Lung Rejection Study Group. MEASUREMENTS AND RESULTS: The positivity rate and complication rate were determined for the procedures. In procedures performed for clinical indications, the sensitivity for the diagnosis of acute rejection and cytomegalovirus pneumonia was calculated by a decision-to-treat analysis. A specific histologic diagnosis was detected in 69 percent of the clinical procedures, 57 percent of the surveillance procedures, and 64 percent of the follow-up procedures. For clinical indications, the sensitivity of transbronchial lung biopsy was 72 percent for the diagnosis of acute rejection and 91 percent for the diagnosis of cytomegalovirus pneumonia. Surveillance biopsy specimens often showed clinically inapparent rejection or cytomegalovirus pneumonia. The overall complication rate was 8.9 percent; none of the complications were life threatening. CONCLUSIONS: Transbronchial lung biopsy is a useful and safe procedure in the treatment of lung transplant recipients. When performed for clinical indications, the procedure proved to be sensitive for the diagnosis of acute rejection and cytomegalovirus pneumonia. When performed for surveillance in clinically and physiologically stable recipients, the incidence of rejection and cytomegalovirus pneumonia was unexpectedly high; the potential clinical implications of these findings will require further study.

Biopsy, Needle↗

PubMed1992

Single lung transplantation for pulmonary hypertension. Technical aspects and immediate hemodynamic results.

Donor availability has limited the clinical applicability of heart-lung transplantation in patients with end-stage pulmonary hypertension. Satisfaction with single lung transplantation in other patient groups prompted its extension to patients with pulmonary hypertension. Nine patients with end-stage pulmonary hypertension underwent single lung transplantation. Important technical considerations included routine use of cardiopulmonary bypass, simultaneous closure of significant associated cardiac defects (n = 4), and use of remaining thoracic donor organs in multiple recipients (total thoracic transplants from eight donors = 21). Analysis of immediate postoperative hemodynamics suggests that early relief of pulmonary hypertension and improvement in right ventricular function can be expected. There was one postoperative death. Eight patients have been discharged and are alive and well at a mean follow-up period of 1 year. All eight survivors have returned to New York Heart Association functional class I from their preoperative levels of III or IV. These results support the use of single lung transplantation as a transplant option in patients with end-stage pulmonary hypertension. The question of long-term durability remains unanswered.

Adult↗

PubMed1992

Morbidity, mortality, and early results of single versus bilateral lung transplantation for emphysema.

Both single lung transplantation and bilateral lung transplantation have been successful in patients with chronic obstructive pulmonary disease. Limited availability of donor lungs dictates wider use of single lung transplantation as long as this procedure provides a comparable functional result at less risk. Early morbidity, mortality rates, and functional results were compared in 32 consecutive patients undergoing either single or bilateral lung transplantation for end-stage chronic obstructive pulmonary disease. When pretransplantation and posttransplantation values of forced expiratory volume in 1 second, single breath diffusing capacity, total lung capacity, arterial oxygen tension, and 6-minute walking distance were compared, statistically significant improvement (p less than 0.01) was seen in both groups. However, significantly higher values (p less than 0.01) were attained for forced expiratory volume in 1 second, single breath diffusing capacity, and arterial oxygen tension in the bilateral transplantation group than in the single lung transplantation group. Patients receiving bilateral lung transplants were at greater risk for postoperative complications, especially cardiac arrhythmias and bronchial anastomotic defects. Actuarial survival for the single lung transplantation group was 93% at 1 year, versus 87% at 6 months and 71% at 1 year for the bilateral lung transplantation group. The optimal transplantation procedure for patients with chronic obstructive pulmonary disease has not been determined. Longer follow-up periods are needed to define better the roles of bilateral and single lung transplantation in this group of patients.

Age Factors↗

PubMed1992

Lung transplantation. Analysis of thirty-six consecutive procedures performed over a twelve-month period. The Washington University Lung Transplant Group.

A consecutive series of 36 lung transplant procedures in 35 patients, performed over a 12-month period, has been reviewed. There were 14 men and 21 women undergoing 23 single, 12 bilateral, and one en bloc double lung transplant. There were one hospital death and three late deaths in the series, giving a hospital survival rate of 97.2% and a 1-year actuarial survival figure of 91.7%. Airway complications occurred in six patients (17.2%), one of whom died. Cytomegalovirus infection was demonstrated in 18 patients (51%), but no deaths have resulted. The most common cardiac complication was an atrial tachyarrhythmia (nine patients, 25.7%) and three patients had a cardiac arrest, but all were successfully resuscitated. Twelve patients required a further 25 surgical procedures after transplantation; however, renal and hematologic complications were uncommon. The prevalence and management of the other associated complications is discussed.

Adult↗

PubMed1991

The Washington University-Barnes Hospital experience with lung transplantation. Washington University Lung Transplantation Group.

OBJECTIVE: --To review our experience with lung transplantation, emphasizing recipient selection, choice of procedure, functional results, and outcome. DESIGN: --Retrospective review of patients who received lung transplants at Barnes Hospital, St Louis, Mo, between July 1, 1988, and January 31, 1991. SETTING: --Washington University School of Medicine, St Louis, Mo, and Barnes Hospital, a medical school and its affiliated referral hospital, respectively. PATIENTS: --Sixty-nine lung transplant procedures were performed in 66 recipients. Patients with clinically and physiologically severe lung disease were selected according to predetermined guidelines. Underlying diseases in the recipients included chronic obstructive pulmonary disease, alpha 1-antitrypsin deficiency emphysema, cystic fibrosis, pulmonary fibrosis, primary pulmonary hypertension, Eisenmenger's syndrome associated with an atrial septal defect, bronchiectasis, eosinophilic granuloma, and lymphangiomyomatosis. INTERVENTION: --Double-lung, bilateral sequential, and single-lung transplantations were performed. Eight patients underwent en bloc double-lung transplantations or a modification of this procedure with separate bronchial anastomoses. Thereafter, the bilateral sequential approach to replacement of both lungs was performed in 26 patients. Thirty-two patients underwent single-lung transplantations. MAIN OUTCOME MEASURES: --Pulmonary function tests, arterial blood gas levels, pulmonary artery pressure, pulmonary vascular resistance, and actuarial survival. RESULTS: --Actuarial survival at 1 year for the 66 lung transplant recipients was 79%. Actuarial survival at 1 year was 82% for the bilateral lung transplant recipients and was 90% for the single-lung transplant recipients. In patients with either restrictive or obstructive lung disease, pulmonary function tests and arterial blood gas levels improved markedly after lung transplantation. In patients with primary pulmonary hypertension or Eisenmenger's syndrome, the pulmonary artery pressure decreased and the cardiac index increased into the normal range after single-lung transplantation. CONCLUSIONS: --In carefully selected patients with end-stage lung disease, single-lung and bilateral lung transplantations can significantly improve functional capacity, with promising early actuarial survival statistics after 1 year.

Actuarial Analysis↗

PubMed1991

Bilateral sequential lung transplantation: the procedure of choice for double-lung replacement.

We recently described a technique for bilateral sequential lung transplantation that replaces the en bloc double-lung operation, a procedure that was accompanied by frequent problems with airway healing. Twenty-seven patients have undergone 28 bilateral sequential lung transplantations over the past 14 months. Eighteen patients had transplantation because of end-stage emphysema; 6, cystic fibrosis; and 1 each, obliterative bronchiolitis, usual interstitial pneumonitis with pulmonary fibrosis, and bronchiectasis. Cardiopulmonary bypass was used electively in the first 5 patients until it was recognized that the procedure could be done safely without it, and in only 3 additional recipients has it been employed. Mean ischemic time for the first lung was 276 +/- 43 minutes and for the second lung, 410 +/- 64 minutes. There have been five deaths, three in the postoperative period (11% operative mortality) and two late. The other patients are alive and well and do not require oxygen 2 to 15 months after transplantation. Mean forced expiratory volume in 1 second rose from 16% +/- 8% of predicted to 84% +/- 17% at 12 weeks. Six-minute walk values increased from a mean of 251 +/- 91 m to 666 +/- 42 m at 24 weeks. The excellent exposure afforded to both hemithoraces by the thoracosternotomy incision and the rare need of cardiopulmonary bypass have allowed us to offer the option of transplantation to patients who formerly would have been turned down because of previous pulmonary resection or pleurectomy. On four occasions, ventilator-dependent patients underwent successful transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Regional myocardial stress distribution from magnetic resonance image-based mathematical models.

The instantaneous regional stress distribution within the myocardium, which cannot be directly measured, has been estimated using improved numerical methods and nonaxisymmetric biventricular geometry. To do this, we have employed computer-aided solid mathematical modeling to generate a three-dimensional representation for an ex vivo canine biventricular unit using magnetic resonance imaging. A two-dimensional transverse section was isolated from the solid mathematical model for regional stress analysis using p-version finite element analysis. Loading conditions and material property descriptions were taken from published reports. Analyses showed the maximum principal stresses to range from -1.76 X 10(5) to 8.52 X 10(5) dynes/cm2 during systolic loading, and from -3.85 X 10(4) to 1.13 X 10(5) dynes/cm2 during diastolic loading. This study demonstrates that magnetic resonance image-based solid mathematical biventricular models are suitable for regional stress analysis using p-version finite element analysis. p-Version finite element analysis using magnetic resonance image-based cardiac representations facilitates in vivo stress-strain analyses and may allow the clinical estimation of regional myocardial stress.

Animals↗

PubMed1991

Single-lung transplantation for pulmonary hypertension. Three-month hemodynamic follow-up.

BACKGROUND: Shorter waiting times, relative technical simplicity, and satisfactory application to a broad spectrum of patients has made single-lung transplantation an attractive option in the treatment of patients with end-stage pulmonary hypertension. METHODS AND RESULTS: Seven patients with pulmonary hypertension underwent single-lung transplantation. Simultaneous closure of associated atrial septal defects was accomplished in two patients. Despite severely compromised pretransplant right ventricular function in all patients, there was no early or late mortality. Right ventricular functional recovery as characterized by hemodynamic assessment before and at a mean of 13 weeks posttransplant was nearly uniform and characterized by a drop in 1) pulmonary arterial systolic pressure from 92 +/- 7 mm Hg to 29 +/- 6 mm Hg (p = 0.001), 2) central venous pressure from 10 +/- 6 mm Hg to 1 +/- 2 mm Hg (p = 0.02), and 3) pulmonary vascular resistance index from 1,924 +/- 663 to 232 +/- 73 dyne.sec.cm-9 (p = 0.001). Radionuclide ventriculography before and at a mean of 17 weeks posttransplant documented a significant (p = 0.006) increase in right ventricular ejection fraction from 22 +/- 15% to 51 +/- 11%. Quantitative pulmonary perfusion scintigraphy at a mean of 17 weeks posttransplant demonstrated a significant (p = 0.001) increase in perfusion to the transplanted lung from 56 +/- 6% to 89 +/- 7%. There was a concomitant, slight but significant (p = 0.004) decrease in ventilation to the transplanted side from 56 +/- 6% to 49 +/- 8%. After transplantation, all patients returned to New York Heart Association functional class I or II from their preoperative levels of class III or IV. CONCLUSIONS: These early follow-up data cautiously support the option of single-lung transplantation in patients with pulmonary hypertension, although long-term durability of these hemodynamic changes deserves documentation before widespread application.

Follow-Up Studies↗