Right ventricular adaptation to increased afterload after orthotopic cardiac transplantation in the setting of recipient chronic pulmonary hypertension

BACKGROUND

Right ventricular (RV) failure remains an important risk factor for early morbidity and mortality after orthotopic cardiac transplantation and is most commonly related to preexistent chronic pulmonary hypertension (CPH) in the recipient, which occurs secondary to long-standing congestive heart failure. This study was designed to assess the compensatory mechanisms of the acutely transplanted RV in the setting of recipient CPH using a canine model of bicaval cardiac transplantation (TX) and monocrotaline pyrrole (MCTP)-induced CPH.

METHODS AND RESULTS

Twenty adult mongrel dogs were used for 10 successfully completed TX experiments. Recipients received an injection of 3 mg/kg MCTP 4 months before TX. RV function was assessed with load-insensitive means (preload recruitable stroke work), and Fourier analysis was used to calculate RV hydraulic power and transpulmonary efficiency. At the time of TX, significant increases in the mean pulmonary artery pressure, mean right ventricular pressure, and pulmonary vascular resistance were observed in recipients compared with donors and were further significantly increased after cardiopulmonary bypass. Significant increases in RV preload recruitable stroke work and RV hydraulic power were observed after TX compared with before TX and occurred in association with significant decreases in transpulmonary efficiency.

CONCLUSIONS

Significant increases in pulmonary hemodynamic indexes occurred after MCTP injection and were further significantly increased after cardiopulmonary bypass. In the setting of recipient CPH, RV performance adapts acutely after bicaval TX with significant increases in power and contractility. However, a significant decrease in transpulmonary efficiency was also observed, which may improve over time as the RV adapts to the increased afterload.

Infections in patients with cystic fibrosis following lung transplantation

BACKGROUND

There is controversy over whether colonization with drug-resistant organisms is a contraindication to lung transplantation.

METHODS

We undertook a retrospective review of the results of lung transplantation for patients with cystic fibrosis (CF) at Duke University Medical Center.

RESULTS

As of May 1996, 21 patients with CF underwent bilateral lung transplantation. The first patient died within 24 h of transplantation from sepsis due to Stenotrophomonas maltophilia. Of the remaining 20 patients, 17 (85%) are alive and in stable condition. The three deaths were related primarily to bronchiolitis obliterans at 4 and 18 months in two patients and to cytomegalovirus pneumonitis at 5 months in the other patient. The 17 surviving patients have been followed up for a mean of 13 months (range, 0.5 to 34 months). Most of them were colonized and infected with multidrug-resistant organisms before transplantation. Following transplantation, 11 patients had complications from infections. One patient had bacteremia due to a panresistant Burkholderia cepacia and was treated successfully. Two patients had bacteremia and wound infection due to Burkholderia gladioli, previously thought to be pathogenic only in plants. Both patients were treated successfully. Of the six patients with Aspergillus fumigatus isolated from cultures before transplantation, only one had invasive disease following transplantation and responded to treatment.

CONCLUSION

The organisms present before transplantation were not the primary cause of mortality in our patient population. Our findings suggest that lung transplantation should be considered in CF patients infected with multidrug-resistant organisms.

The role of natural anti-Gal alpha 1-3Gal antibodies in hyperacute rejection of pig-to-baboon cardiac xenotransplants

Xenoreactive natural antibodies in humans and higher primates are directed predominantly at Gal alpha 1-3Gal. These antibodies are thought to initiate hyperacute rejection of porcine organ xenografts. The contribution of anti-Gal alpha 1-3Gal antibodies to the xenoractive natural antibody repertoire and to the initiation of hyperacute rejection was tested in a pig-to-baboon cardiac xenograft model. Anti-Gal alpha 1-3Gal antibodies were depleted from baboons by extracorporeal absorption of anti-Gal alpha 1-3Gal antibodies from plasma using columns with a matrix bearing Gal alpha 1-3Galb1-4GlcNAc. Specific removal of anti-Gal alpha 1-3Gal antibodies was achieved prior to transplantation as demonstrated by immunoassay. Porcine hearts were then transplanted into these baboons and the outcome of the transplants was analysed. Immunofluorescence revealed little deposition of baboon antibodies in the grafts. The porcine hearts did not undergo hyperacute rejection even though complement activity was approximately 90% of baseline at the time of transplantation. These findings demonstrate that anti-Gal alpha 1-3Gal antibodies constitute a major fraction of xenoreactive natural antibodies in primate blood and that these antibodies contribute significantly to the pathogenesis of hyperacute xenograft rejection.

Preliminary report of a genetic basis for cognitive decline after cardiac operations. The Neurologic Outcome Research Group of the Duke Heart Center

BACKGROUND

Changes in memory and cognition frequently follow cardiac operations. We hypothesized that patients with the apolipoprotein E-epsilon 4 allele are genetically predisposed to cognitive dysfunction after cardiac operations.

METHODS

The apolipoprotein E-epsilon 4 allele was evaluated as a predictor variable for postoperative cognitive dysfunction in 65 patients undergoing cardiac bypass grafting at Duke University Medical Center. The primary outcome measure was performance on a cognitive battery administered preoperatively and at 6 weeks postoperatively.

RESULTS

In a multivariable logistic regression analysis including apolipoprotein E-epsilon 4, preoperative score, age, and years of education, a significant association was found between apolipoprotein E-epsilon 4 and change in cognitive test score in measures of short-term memory at 6 weeks postoperatively. Patients with lower educational levels were more likely to show a decline in cognitive function associated with the apolipoprotein E-epsilon 4 allele.

CONCLUSIONS

This study suggests that apolipoprotein E genotype is related to cognitive dysfunction after cardiopulmonary bypass. Cardiac surgical patients may be susceptible to deterioration after physiologic stress as a result of impaired genetically determined neuronal mechanisms of maintenance and repair.

Radiologic issues in lung transplantation for end-stage pulmonary disease

Lung transplantation has evolved into an effective therapy for end-stage pulmonary disease. The radiologist has an important role in the management of these patients before and after transplantation. Unfortunately, the radiologic findings of the major complications (i.e., reperfusion edema, infection, rejection) that occur after transplantation overlap and are often nonspecific. Clinical correlation, bronchoalveolar lavage, and transbronchial biopsy are usually required for accurate differentiation. The following rules of thumb may be helpful: Radiographic opacities seen during the first week are usually due to reperfusion edema: persistent or progressive opacities beyond the first week suggest infection or acute rejection: infection in the first month is usually bacterial, and opportunistic pneumonia is more common thereafter, nodular opacities are usually due to infection or posttransplantation lymphoproliferative disorders but can also be due to transbronchial lung biopsy; and progressive bronchial dilatation and air trapping seen on expiratory CT are useful signs of BOS.

Effects of nitric oxide after cardiac transplantation in the setting of recipient pulmonary hypertension

BACKGROUND

Recipient pulmonary hypertension secondary to chronic congestive heart failure is a significant risk factor for right ventricular failure after cardiac transplantation. In this study, the hemodynamic and inotropic effects of nitric oxide (NO) were examined after bicaval cardiac transplantation in the setting of monocrotaline pyrrole-induced recipient chronic pulmonary hypertension.

METHODS

Twenty dogs underwent 10 successfully completed transplantation experiments. Recipients underwent pulmonary artery injection of 3 mg/kg monocrotaline pyrrole 4 months before transplantation. Measurements were taken 1 hour after cessation of cardiopulmonary bypass and after NO inhalation. Pulmonary vascular impedance was calculated using Fourier analysis, and cardiac function was assessed with load-insensitive means (preload recruitable stroke work).

RESULTS

At the time of transplantation, the precardiopulmonary bypass levels of pulmonary vascular resistance in recipient animals were significantly greater when compared with donor levels, and were further significantly increased after cardiopulmonary bypass. Three recipients died after transplantation secondary to acute right ventricular failure. In the surviving animals, NO led to significant improvements in pulmonary vascular resistance and vascular impedance, which occurred in association with significant increases in transpulmonary efficiency. No significant changes were observed in right and left ventricular preload recruitable stroke work after NO inhalation.

CONCLUSIONS

These data suggest that NO may be an effective means to improve vascular impedance and pulmonary vascular efficiency after cardiac transplantation in the setting of recipient chronic pulmonary hypertension.

Hemodynamic and inotropic effects of nitric oxide in pulmonary hypertension

Right ventricular failure following cardiac transplantation is most commonly related to pre-existent recipient pulmonary hypertension secondary to chronic congestive heart failure. Although nitric oxide has had some role clinically in improving pulmonary hemodynamics and right ventricular function in this setting, an appropriate large-animal model of stable pulmonary hypertension has not been available for basic investigation of this problem. This study was designed to examine the hemodynamic and inotropic effects of inhaled nitric oxide using a canine model of monocrotaline pyrrole-induced chronic pulmonary hypertension. Eight mongrel dogs (22-25 kg) were used. All animals underwent percutaneous pulmonary artery catheterization to measure right heart hemodynamics prior to and 8 weeks after a right atrial injection of monocrotaline pyrrole. Eight weeks post-injection, all hearts were instrumented with a pulmonary artery flow probe, sonomicrometric dimension transducers, and micromanometers. Data were collected at baseline and following nitric oxide administration. Eight weeks post-monocrotaline pyrrole injection, significant increases were observed in the pulmonary hemodynamics compared to pre-injection. Nitric oxide led to significant decreases in pulmonary vascular impedance. Significant improvements in pulmonary blood flow, transpulmonary efficiency, and right ventricular contractility were also observed. This investigation demonstrates the well-known clinical effects of nitric oxide in improving pulmonary hemodynamics which were also associated with an increase in pulmonary blood flow, transpulmonary efficiency, and right ventricular contractility in the setting of monocrotaline pyrrole-induced pulmonary hypertension.

Nitric oxide improves pulmonary vascular impedance, transpulmonary efficiency, and left ventricular filling in chronic pulmonary hypertension

OBJECTIVE

Chronic pulmonary hypertension is difficult to treat and despite the introduction of several therapeutic options, no single therapy is universally recommended. Nitric oxide has had some role clinically in improving pulmonary hemodynamics in this setting; however, basic investigation has not been performed in an appropriate large animal model of stable pulmonary hypertension. This study was designed to examine the effects of inhaled nitric oxide on pulmonary hemodynamics in the setting of a canine model of monocrotaline pyrrole-induced chronic pulmonary hypertension and used Fourier analysis for assessment of pulmonary vascular impedance.

METHODS

Sixteen mongrel dogs (22 to 25 kg) were used. Animals underwent percutaneous pulmonary artery catheterization to measure-right-sided hemodynamics before and 6 weeks after a right atrial injection of either monocrotaline pyrrole (n = 8) or placebo (n = 8). Six weeks after the injection all hearts were instrumented with an ultrasonic flow probe, sonomicrometric dimension transducers, and micromanometers. Data were collected at baseline and after nitric oxide administration. Harmonic derivation of functional data was achieved with Fourier analysis.

RESULTS

Six weeks after the injection, significant increases in pulmonary artery pressure and pulmonary vascular resistance were observed in the monocrotaline pyrrole group. Nitric oxide led to significant decreases in pulmonary vascular impedance. Significant improvements in pulmonary blood flow, transpulmonary efficiency, and left ventricular filling were also observed.

CONCLUSIONS

This investigation demonstrates the well-known clinical effects of nitric oxide in improving pulmonary hypertension, which were also associated with an increase in pulmonary blood flow, transpulmonary efficiency, and left ventricular filling in the setting of monocrotaline pyrrole-induced pulmonary hypertension.

Endotoxin concentration in contact lens storage cases

BACKGROUND

The contamination of contact lens storage cases by gram-negative bacteria has been associated with ulcerative keratitis. This study investigated the concentration of endotoxin, a substance produced by gram-negative bacteria, in contact lens cases.

METHODS

The limulus amebocyte lysate (LAL) test was used to measure the concentration of endotoxin in the storage cases of 27 contact lens wearers. The units of concentration used were endotoxin units per ml (EU/ml). The type of storage solution used by each patient, as well as other aspects of lens care and use, were recorded.

RESULTS

Twenty-one storage cases--78% of those tested--contained measurable amounts of toxin. Two cases contained extremely high concentrations of endotoxin: 60 EU/ml and 300 EU/ml. Both cases were from persons using Opti-Free. Cases from six persons using Opti-Free accounted for five of the top seven endotoxin concentrations when cases were ranked on that basis. Fewer hours of daily lens wear and lower lens age were also possibly associated with higher concentrations of endotoxin, although those associations may have resulted by chance (p = 0.057 and p = 0.095, respectively).

CONCLUSIONS

The LAL test was useful in estimating the degree of contamination of cases by gram-negative bacteria. Most cases contained measurable amounts of endotoxin, indicating at least some contamination by gram-negative bacteria. The effectivity of Opti-Free in inhibition of bacterial growth in contact lens cases should be investigated further.

An adult canine model of chronic pulmonary hypertension for cardiopulmonary transplantation

BACKGROUND

This study establishes a chemically-induced canine model of chronic pulmonary hypertension (CPH) using monocrotaline pyrrole (MCTP) and then characterizes this model in terms of hemodynamic, morphologic, and cardiac functional changes.

METHODS

Thirty-three adult mongrel dogs (22 to 25 kg) were used. All animals underwent pulmonary artery catheterization to measure central venous pressure, mean right ventricular pressure (mRVP), mean pulmonary artery pressure (mPAP), and pulmonary capillary wedge pressure before and 6 weeks after a right atrial injection of either 60 mg/kg monocrotaline (group A, n = 8), 5 mg/kg MCTP (group B, n = 4), 3 mg/kg MCTP (group C, n = 13) or placebo (control, n = 8). Six weeks after injection, hearts in control and group C dogs were instrumented with flow probes, dimension transducers, and micromanometers to measure dynamic ventricular pressures and volumes.

RESULTS

No significant differences in baseline hemodynamic indexes were observed between groups. All animals in group B and five in group C died after MCTP injection as a result of pulmonary edema. No significant increase in any hemodynamic parameters occurred in group A or in control dogs 6 weeks after injection. In group C, significant increases in central venous pressure, mRVP, and mPAP were observed 6 weeks after injection. Significant increases in right ventricular (RV) function and the weight ratio of the RV to left ventricle were observed in group C when compared with controls.

CONCLUSIONS

A chemically-induced canine model of CPH has been created. Significant increases in mRVP, mPAP, and pulmonary capillary wedge pressure were observed 6 weeks after MCTP injection. RV function adapts to the increased afterload in the short term without evidence of failure. A stable model of pulmonary hypertension is provided as a potential means to evaluate posttransplantation RV dysfunction in the setting of CPH.

A case of disseminated infection with Nocardia brasiliensis in a lung transplant recipient

BACKGROUND

Infection with Nocardia species is an increasingly recognized complication of solid organ transplantation. Nocardia asteroides accounts for most transplant-related nocardiosis, while Nocardia brasiliensis rarely causes infection in organ transplant recipients.

METHODS

We describe a case of disseminated infection with N brasiliensis in a single-lung transplant recipient who also had concomitant infections with viral and fungal organisms.

RESULTS

Although the mortality rate is high in immunocompromised patients with disseminated Nocardia infection, our patient responded favorably to prolonged antimicrobial therapy.

CONCLUSIONS

This case illustrates that N brasiliensis, like N asteroides, produces pulmonary disease and dissemination in solid organ transplant recipients, and demonstrates the utility of prolonged treatment with trimethoprim-sulfamethoxazole in Nocardia infections.

Telescoping bronchial anastomoses for unilateral or bilateral sequential lung transplantation: CT appearance

PURPOSE

To determine the computed tomographic (CT) appearance of telescoping bronchial anastomoses.

MATERIALS AND METHODS

CT scans obtained in 36 adult patients with 54 telescoping anastomoses (30 right bronchus, 24 left bronchus) were retrospectively reviewed. Seventeen scans were obtained with 10-mm collimation, one with 5-mm collimation, and 18 with 3-mm collimation. Multiplanar volume reconstruction images were retrospectively generated in 19 patients. CT findings were correlated with fiberoptic bronchoscopic findings and clinical records.

RESULTS

Smooth, spherical air collections caused by diverticula of redundant mucosa were seen at the inferior or medial aspect of 22 anastomoses (41%). Endoluminal flaps and linear air collections caused by separation of the invaginated bronchus from the recipient bronchus were seen in 16 anastomoses (30%). Flaps and linear air collections were seen only at the anterior, superior, or inferior aspects of the anastomosis. Flaps and diverticula were more common at right anastomoses than at left anastomoses. No patient with an endoluminal flap or diverticulum at CT had dehiscence at bronchoscopy. Irregular air collections or posterior wall defects were suggestive of dehiscence at four anastomoses (7%). Dehiscence was confirmed bronchoscopically at two of these four anastomoses.

CONCLUSION

Endoluminal flaps and linear or spherical air collections can be a normal feature of the telescoping anastomosis and should not necessarily be interpreted as dehiscence.

Milrinone improves pulmonary hemodynamics and right ventricular function in chronic pulmonary hypertension

BACKGROUND

Right ventricular failure after cardiac transplantation is commonly related to preexisting recipient pulmonary hypertension. This study was designed to investigate the effects of intravenous milrinone on pulmonary hemodynamic indices and right ventricular function in a canine model of monocrotaline pyrrole-induced chronic pulmonary hypertension.

METHODS

Eight mongrel dogs underwent pulmonary artery catheterization to measure right-sided hemodynamic indices before and 6 weeks after a right atrial injection of monocrotaline pyrrole. Six weeks after injection, all hearts were instrumented with a pulmonary artery flow probe, ultrasonic dimension transducers, and micromanometers. Data were collected at baseline and after milrinone infusion.

RESULTS

Six weeks after monocrotaline pyrrole injection, significant increases in the pulmonary artery pressure and pulmonary vascular resistance were observed. Milrinone led to significant increases in right ventricular function as well as significant improvements in pulmonary vascular resistance, pulmonary blood flow, and left ventricular filling.

CONCLUSIONS

This investigation demonstrates the well-known hemodynamic and inotropic effects of milrinone which, in the setting of monocrotaline pyrrole-induced pulmonary hypertension, were also associated with significant increases in pulmonary blood flow and left ventricular filling.

Pulmonary hemodynamics and blood flow characteristics in chronic pulmonary hypertension

BACKGROUND

Lung transplantation is now an acceptable form of therapy for pulmonary hypertension, but controversy remains regarding the most appropriate surgical procedure. In this study, the changes in pulmonary vascular mechanics occurring in the setting of pulmonary hypertension were investigated using an adult canine model of monocrotaline pyrrole-induced pulmonary hypertension.

METHODS

Animals underwent pulmonary artery catheterization to measure right heart pressures before and 8 weeks after injection of either 3 mg/kg of monocrotaline pyrrole (n = 8) or placebo (n = 8). Eight weeks after injection, hearts underwent instrumentation with an ultrasonic flow probe and micromanometers. Harmonic derivation of functional data was achieved with Fourier analysis.

RESULTS

Significant increases in mean pulmonary artery pressure and pulmonary vascular resistance were observed after monocrotaline pyrrole injection. There was no significant difference in pulmonary blood flow. However, significant increases in input resistance and right ventricular hydraulic power with significant decreases in transpulmonary efficiency were observed.

CONCLUSIONS

Pulmonary hypertension causes significant alterations in pulmonary hemodynamics. Pulmonary blood flow is maintained by a significant increase in total power but with a significant decrease in transpulmonary efficiency. This adult canine model of pulmonary hypertension provides a useful means by which to evaluate surgical options of lung transplantation for improving pulmonary hemodynamics in the setting of chronic pulmonary hypertension.

The MCMI--III: Present and Future Directions

Both the original Millon Clinical Multiaxial Inventory (MCMI-I; Millon, 1977) and the Millon Clinical Multiaxial Inventory-II (MCMI-II; Millon, 1987) were refined and strengthened on a regular basis by both theoretic logic and research data. This aspiration has continued. The new Millon Clinical Multiaxial Inventory-III (MCMI-III; Millon, 1994) has been further coordinated with the most recent official diagnostic schema, the Diagnostic and Statistical Manual of Mental Disorders (4th ed., [DSM-IV]; American Psychiatric Association [APA], 1994) in an even more explicit way than before. Although the publication of the first version of the MCMI preceded the publication of the DSM-IV, its author played a major role in formulating the official manual's personality disorders, contributing thereby to their conceptual correspondence. The DSM-III-R (APA, 1987) was subsequently published in the same year as the MCMI-II; the inventory was modified in its final stages to make it as consonant as possible with the conceptual changes introduced in the then forthcoming official classification. The present version of the MCMI, the MCMI-III, strengthens these correspondences further by drawing on many of the diagnostic criteria of the DSM-IV to serve as the basis for drafting the inventory's items. This article reports on a select set of theoretical and empirical developments that are being carefully weighed for possible inclusion in future MCMIs, or as a guide in the refinement process of future MCMIs.

Swine lungs expressing human complement-regulatory proteins are protected against acute pulmonary dysfunction in a human plasma perfusion model

Pulmonary transplantation is currently limited by the number of suitable cadaver donor lungs. For this reason, pulmonary xenotransplantation is currently being investigated.

OBJECTIVE

Our goal was to assess the role of complement in pulmonary xenograft dysfunction.

METHODS

The pulmonary function of swine expressing human decay accelerating factor and human CD59 (n = 6) was compared with that of the lungs from nontransgenic (control) swine (n = 6) during perfusion with human plasma.

RESULTS

After 2 hours of perfusion, the pulmonary vascular resistance was 1624 +/- 408 dynes.sec.cm-5 in control lungs and 908 +/- 68 dynes.sec.cm-5 in transgenic lungs (p < 0.05). Control lungs had a venous oxygen tension of 271 +/- 23 mm Hg with a ratio of venous oxygen tension to inspired oxygen fraction of 452 +/- 38 at 2 hours of perfusion; transgenic lungs had a venous oxygen tension of 398 +/- 11 mm Hg and a ratio of venous oxygen tension to inspired oxygen fraction of 663 +/- 18 (p < 0.05). Control lungs showed a decrease of 79.8% +/- 3.7% in static pulmonary compliance by 2 hours, versus a 12.0% +/- 8.1% decrease by the transgenic lungs (p < 0.05). The control lungs also developed 561.7 +/- 196.2 ml of airway edema over 2 hours, in contrast to 6.5 +/- 1.7 ml in transgenic lungs (p < 0.05).

CONCLUSION

Lungs from swine expressing human decay accelerating factor and human CD59 functioned better than nontransgenic swine lungs when perfused with human plasma. These results suggest that complement activation is involved in producing acute pulmonary xenograft dysfunction and demonstrate that lungs from swine expressing human decay accelerating factor and human CD59 are protected against pulmonary injury when perfused with human plasma.

Right ventricular failure--insights provided by a new model of chronic pulmonary hypertension

This study was designed to examine the effects of both nitric oxide and milrinone on pulmonary hemodynamics and right ventricular function using a newly established model of monocrotaline pyrrole-induced chronic pulmonary hypertension. Sixteen mongrel dogs (23-25 kg) were used. All animals underwent percutanous pulmonary artery catheterization to measure right heart hemodynamics prior to and 8 weeks after a right atrial injection of either monocrotaline pyrrole (MCTP, n=8) or placebo (CTL, n=8). Eight weeks postinjection, all hearts were instrumented with a pulmonary artery flow probe and intracavitary micromanometers. Data were collected at baseline as well as following both nitric oxide and milrinone administration. There was no significant difference in the baseline hemodynamic measurements between the two groups. Eight weeks postinjection, significant increases in the pulmonary artery pressure and pulmonary vascular resistance were observed in MCTP compared with CTL. Both nitric oxide and milrinone resulted in significant improvements in pulmonary vascular resistance, pulmonary blood flow, and right ventricular contractility. In addition, nitric oxide caused a significant improvement in pulmonary artery pressure and transpulmonary efficiency, while milrinone led to a significant increase in right ventricular hydraulic power. This study demonstrates the well-known clinical effects of nitric oxide and milrinone in improving pulmonary hypertension, which were also associated with an increase in pulmonary blood flow, transpulmonary efficiency, and right ventricular hydraulic power in the setting of monocrotaline pyrrole-induced chronic pulmonary hypertension.

Effect of temperature during cardiopulmonary bypass on gastric mucosal perfusion

The purpose of our study was to prospectively study the splanchnic response to hypothermic and tepid cardiopulmonary bypass (CPB) using alphastat management of arterial blood-gas tensions. Twenty-four patients for elective CABG surgery were allocated randomly to tepid (35-36 degrees C) or hypothermic (30 degrees C) bypass groups. Measurements were made at four times: (1) baseline, (2) stable during CPB (inflow temperature = nasopharyngeal temperature) 30 degrees C for hypothermic patients, bypass +20 min for tepid patients, (3) 10 min before the end of bypass, (4) after bypass, skin closure. Both groups demonstrated a significant reduction in gastric intramucosal pH (pHim) from time 1 to time 4 and there was no difference in the incidence of a low pHim between the tepid and cold groups (4/12 vs 3/12; ns) at time 4. pHim was significantly lower in the tepid groups at time 3 (P = 0.03) but this discrepancy may have been because of an artefactually high pHim in the cold group. There was a significantly higher incidence of postoperative non-cardiac complications in patients who had a low pHim at time 4 (P = 0.0008). Therefore, we conclude that although the temperature during CPB had a transient effect on pHim it is unlikely to be a major determinant in the pathogenesis of gut mucosal hypoperfusion after bypass.

Brain death further promotes ischemic reperfusion injury of the rabbit myocardium

BACKGROUND

Little is known about preload-dependent cardiac function after brain death (BD) and subsequent graft preservation.

METHODS

A validated model of BD in rabbits was developed and myocardial performance was studied after BD induction and 1 hour of subsequent global hypothermic ischemia using a validated rabbit model and an isolated work-performing heart preparation.

RESULTS

Significant decreases in stroke work, left ventricular contractility, and left ventricular relaxation were observed 2 hours after BD. After global hypothermic ischemia, significant decreases in stroke work, left ventricular contractility, and left ventricular relaxation were observed in the BD group compared with controls. Cardiac output and coronary flow were also significantly decreased in BD hearts compared with controls. Creatine kinase release was increased by 32.5% in BD hearts compared with controls.

CONCLUSIONS

In a rabbit model, BD combined with global hypothermic ischemia causes a significant decrease in left ventricular function compared with global hypothermic ischemia. This dysfunction may be attributed to a significant decrease in coronary flows in BD hearts.

Extracellular superoxide dismutase transgene overexpression preserves postischemic myocardial function in isolated murine hearts

BACKGROUND

Myocardial injury after ischemia and reperfusion may be mediated, at least in part, by oxygen-derived free radicals; this supposition is supported by the observation that significant quantities of these radicals are generated during reperfusion. To directly assess the protective effect of extracellular superoxide dismutase (EC-SOD), this study was designed to investigate the ability of EC-SOD overexpression in the hearts of transgenic mice to protect myocardial tissue against ischemiareperfusion injury by use of an isolated work performing murine heart preparation and functional analysis.

METHODS AND RESULTS

Ten transgenic mice (EC.SOD, 28 to 31 g) were studied and compared with 10 control mice (Ctl, 28 to 31 g) in terms of preischemic and postischemic myocardial function. All hearts underwent cardiac harvest and arrest, followed by instrumentation and subsequent reperfusion with warm Krebs-Henseleit solution. Preload-dependent functional analysis was then performed to evaluate cardiac output, contractility (dP/dt), heart rate, stroke work, and stroke volume before and after a 7-minute period of warm ischemia. Results are expressed as mean +/- SEM (ANOVA, paired unpaired t tests). There was no significant difference in preischemic myocardial performance for Ctl and EC-SOD mice. After warm ischemia, cardiac output in EC-SOD was significantly improved compared with Ctl (EC-SOD, 4.55 +/- 0.37 mL/min; Ctl, 2.55 +/- 0.28 mL/min; P < .05). Postischemic dP/dt, stroke work, and stroke volume were also significantly improved in EC-SOD compared with Ctl mice (EC-SOD, 1808 +/- 39 mm Hg/s, 745 +/- 67 dyne.cm, and 13.1 +/- 1.2 microL, respectively; Ctl, 1497 +/- 87 mm Hg/s, 472 +/- 83 dyne.cm, and 8.2 +/- 1.5 microL; P < .05).

CONCLUSIONS

EC-SOD overexpressed mice showed significant improvement in postischemic cardiac function compared with Ctl mice. Thus, EC-SOD overexpressed hearts are less susceptible to mild degrees of ischemia-reperfusion injury than normal hearts.

Effect of perfusion pressure on cerebral blood flow during normothermic cardiopulmonary bypass

BACKGROUND

We have recently shown that during hypothermic cardiopulmonary bypass (CPB), cerebral autoregulation has a positive slope such that for every 10 mm Hg change in pressure, a 0.86 mL.100 g-1.min-1 change in cerebral blood flow (CBF) is predicted. The purpose of this study was to define the influence of mean arterial blood pressure (MAP) on CBF during normothermic CPB.

METHODS AND RESULTS

CBF was measured by use of 133Xe washout and alpha-stat blood gas management during nonpulsatile CPB. CBF measurements were made at a pump flow of 2.4 L.min-1.m-2 at stable normothermia and approximately 15 minutes later after the MAP was increased or decreased > or = 20%. A third data set was recorded after the pressure was returned to the initial value. Forty-five patients were entered into the study. Temperature was held constant. We found a significant effect (P = .016) of change in MAP on change in CBF during normothermic CPB. For a 10 mm Hg increase in MAP, an increase in CBF of 1.78 mL.100 g-1.min-1 is predicted. Along with change in CBF, significant increases in both cerebral metabolic rate and cerebral oxygen delivery were observed.

CONCLUSIONS

This information, along with our previous data shows that autoregulation during CPB has a positive slope that is greater with normothermia than hypothermia. Although it is unlikely that these small changes in flow are an important primary effect in the development of hypoperfusion, increased metabolic rate with increased CBF may indicate pressure-dependent collateral flow potentially in regions embolized during CPB.

Diagnostic yield of bronchoscopies after isolated lung transplantation

Lung transplantation has become an acceptable therapeutic option for end-stage pulmonary diseases. The most common causes of long-term mortality after transplantation are infections and obliterative bronchiolitis (OB). While acute rejection has been shown to be associated with an increased risk of development of OB, cytomegalovirus (CMV) pneumonitis is more controversial as a risk factor for OB. Surveillance bronchoscopies are therefore advocated as a method of detecting silent episodes of CMV pneumonitis or acute rejection. We performed 226 bronchoscopies in 43 lung transplant recipients over 34 months. One hundred fifty-seven of the 226 bronchoscopies were performed according to a surveillance protocol. Acute rejection was diagnosed if lung histologic study revealed grade 2 to 4 rejection or if prompt reversal of clinical deterioration occurred after initiation of pulse steroid therapy. CMV pneumonitis was diagnosed when transbronchial biopsy histologic specimens revealed evidence of CMV inclusion bodies, or when CMV was recovered on BAL fluid in the presence of allograft deterioration. The proportion of patients who were free from any episode of acute rejection or CMV pneumonitis after transplantation was determined by Kaplan-Meier analysis. Twenty-one percent of our transplant recipients were free from acute rejection or CMV pneumonitis after a mean follow-up of 13 months. All patients who had acute rejection or CMV pneumonitis had the initial episode in the first 4 months after transplantation. Patients free of acute rejection or CMV pneumonitis 4 months after transplantation continued to be event free for the duration of follow-up. Our data suggest that surveillance bronchoscopy can be aborted in patients who are free from acute rejection or CMV pneumonitis by 4 months after transplantation. The role of surveillance bronchoscopy in decreasing the incidence of OB or improving survival can be determined only by future randomized prospective trials.

Total pulmonary artery occlusion immediately after lung transplantation: successful revascularization with intravascular stents

Occlusion of the pulmonary artery anastomosis is an uncommon early complication of lung transplantation which necessitates emergency surgical revision. Percutaneous correction of such a complication has not been previously reported. We report a patient who had total pulmonary artery occlusion less than 24 hours after right single lung transplantation with successful revascularization achieved by means of percutaneously delivered endovascular stents.

Survival benefits of heart and lung transplantation

OBJECTIVE

Heart and lung transplantation has gained acceptance as therapy for end-stage cardiac and pulmonary failure. The early and intermediate survival benefits of one center's 10-year experience with 177 patients undergoing thoracic transplantation were examined.

SUMMARY BACKGROUND DATA

As experience in cardiac and pulmonary transplantation has increased, improvements in patient selection, organ preservation, preoperative support, and perioperative care have significantly reduced the early threats to patient survival. Graft dysfunction due to chronic rejection appears to be the main risk for longer-term survival, and data compiled by the United Network for Organ Sharing (UNOS) indicate a 70% 5-year survival for heart transplants and a 50% 5-year survival for lung transplant recipients.

METHODS

The medical records of 120 heart recipients, 52 lung transplant recipients, and 5 heart-lung recipients were reviewed. Cumulative survival estimates were made using Kaplan-Meier analysis. The etiologies of operative and long-term mortality in each transplant population were identified. A comparison of long-term survival after heart transplantation versus coronary revascularization in a group of patients with ischemic cardiomyopathy was performed.

RESULTS

Operative mortality in both the cardiac and pulmonary transplant recipients was 8%. From 1990 to 1995, 70 consecutive adult cardiac transplant procedures were performed without an operative mortality. Three of five patients survived heart-lung transplantation. The extended actuarial survival rate at 5 years was 80% for the cardiac transplant recipients. The 2-year actuarial survival rate for the lung transplant recipients was 88%. Graft dysfunction was the most common cause of operative mortality in the heart transplant group whereas infection was responsible for most of the operative mortality after lung transplantation.

CONCLUSIONS

Cardiac and pulmonary transplantation can be applied to morbidly ill patients with excellent operative and intermediate-term survival.

Fungal infections in lung and heart-lung transplant recipients. Report of 9 cases and review of the literature

We reviewed the pattern and incidence of fungal infections in patients undergoing lung and heart-lung transplantation at Duke University Medical Center from September 1992 until August 1995, and present here 9 illustrative cases. Of the 73 lung and heart-lung transplant recipients studied, 59 (81%) had positive fungal cultures at some point after transplantation. The cases presented here illustrate that lung transplant recipients are predisposed to a wide variety of fungal infections. The clinical pattern of these infections ranges from asymptomatic to rapidly progressive fatal disease. In addition to the reactivation of previous fungal infections and recent exposure to new environmental sources, the donor lung itself can be the source of fungal infection, as we showed by using molecular epidemiology techniques. Because of the associated morbidity and mortality, efforts should be directed at investigating prophylactic antifungal regimens in lung transplant recipients. Preliminary reports on the use of itraconazole and aerosolized amphotericin B have been encouraging. Prospective randomized studies are needed to assess the safety and cost effectiveness of different regimens. Fungal infections in patients after lung transplantation can significantly impede recovery and lead to substantial mortality.