Effects of left ventricular assist devices on outcomes in patients undergoing heart transplantation.

BACKGROUND: Left ventricular assist devices (LVADs) are increasingly being used to "bridge" patients to heart transplantation. METHODS: Data from 40 consecutive status 1 heart transplantation patients treated with intravenous inotrope therapy (n = 20) or the HeartMate LVAD (n = 20) were retrospectively analyzed. RESULTS: Baseline clinical characteristics were similar in the two groups. At the time of transplantation, LVAD patients had significantly higher blood pressure and sodium with significantly lower blood urea nitrogen and creatinine. After transplantation, renal failure (52.6% versus 16.7%) and right heart failure (31.6% versus 5.6%) occurred more frequently (p < 0.05) in the inotrope group. Six-month survival after transplantation did not significantly differ in the inotrope or LVAD groups (73.7% versus 88.9%) but event-free survival was significantly (p < 0.05) lower in the inotrope group (15.8% versus 55.6%). Total hospital charges were significantly lower in the inotrope group ($213,860 +/- $107,560 versus $342,620 +/- $104,420), but average daily hospital charges were not different ($3,990 +/- $1,300 versus $4,130 +/- $2,050). CONCLUSIONS: Status 1 heart transplant patients treated with an LVAD as opposed to inotrope therapy have improved clinical and metabolic function at the time of transplant and improved survival to 6 months after transplant without major complications. Total costs are higher in the LVAD patients but average daily costs are similar.

Conservative management of postoperative chylothorax using somatostatin.

Chylothorax is a rare but serious postoperative complication of thoracic surgical procedures. We report the case of a 77-year-old man who underwent a coronary artery bypass procedure using a left internal mammary artery pedicle graft. A permanent pacemaker was required postoperatively. A persistent postoperative chylothorax developed necessitating continuous drainage and conservative management. Somatostatin was instituted when after 1 week this management failed to resolve the chylothorax. This led to rapid cessation of chyle production. Enteral feeding was reinstituted without complication and surgical intervention was avoided.

Management of acute right heart failure after combined heart and kidney transplantation: case report.

Combined heart and kidney transplantation is performed rarely and merits unique fluid-management considerations postoperatively. We present the case of a young man who developed acute right heart failure after combined heart and kidney transplantation and responded to hemofiltration. We believe that the postoperative management of combined heart and kidney transplant recipients should not be different from that of patients receiving a heart transplant only. Intravenous fluids should be administered judiciously, and hemofiltration should be instituted early to remove fluid and reduce preload if right heart failure develops.

Stage I adenocarcinoma presenting in the pneumonectomy specimen at the time of single lung transplantation.

Two patients at our institution underwent single lung transplantation. The procedure and the patient's postoperative course were uncomplicated in each case. Pathological examination of each pneumonectomy specimen revealed a well-differentiated adenocarcinoma; both were less than 1 cm in size. The remainder of each lung showed no evidence of adenocarcinoma and all lymph nodes were negative. Work-ups for an occult malignancy before and after surgery were negative. This is believed to be the first report of a single lung transplant in a patient with a primary adenocarcinoma of the lung. The implications and management of these patients are discussed.

Myocardial ischemia and infarction postthoracotomy.

The best long-term survival for any given lung cancer patient is provided by surgical resection. However, pneumonectomy still has the highest mortality rates, often due to cardiac complications. Risk assessment can be aided by preoperative evaluation of thoracic surgery patients. The role of right heart function, intraoperative management, and postoperative conditions in myocardial ischemia and infraction are analyzed, and the benefits of different kinds of resection are weighed in light of possible cardiac complications.

Comparative study of solutions for pulmonary preservation using an isolated rabbit lung model.

At the University of Minnesota, University of Wisconsin (UW), modified Euro-Collins (MEC), and Marshall (M) solutions were compared as agents for pulmonary preservation in an isolated rabbit lung model. Normal saline (NS) was used as a control. The heart-lung blocks of donor rabbits were flushed with, and then preserved in, one of the solutions at 4 degrees C. Five rabbits were studied in each group. After 8 h of cold ischemia, the left lung was ventilated and reperfused with fresh venous blood from donor rabbits for 30 min. Pulmonary function was assessed by serial measurements of oxygen (O2) and carbon dioxide (CO2) tensions in blood obtained from the left atrial appendage. The ratios of wet/dry (W/D) weight of the lungs were calculated to assess the extent of pulmonary edema. After 8 h of preservation followed by 30 min of reperfusion, O2 tension was significantly higher with UW (178.36 + 1.72 mmHg). The calculated P values were UW vs NS, < 0.0001; UW vs MEC, 0.154; and UW vs M, 0.0001. CO2 tension with UW was also lower than the other solutions: UW, 35.8 +/- 0.698 mmHg; NS, 48.5 +/- 0.745 mmHg; MEC, 40.69 +/- 0.749 mmHg; and M, 44.68 +/- 0.697 mmHg. The calculated P value was UW vs NS, 0.0001; UW vs MEC, 0.0003; and UW vs M, 0.0001 using repeated-measures analysis of covariance. The W/D ratio was lower with UW as well; UW, 6.82 +/- 0.19; NS, 8.01 +/- 0.23; MEC, 7.28 +/- 0.10; and M, 7.34 +/- 0.17. The P value was < 0.001 using post-hoc tests. In this model, UW solution preserved the lungs better than the other three solutions tested and therefore warrants further clinical application.

Usefulness of surveillance endomyocardial biopsy after pediatric cardiac transplantation.

Endomyocardial biopsy remains the 'gold standard' for the diagnosis of acute rejection after cardiac transplantation, but few guidelines exist to determine the indications for its use in pediatric cardiac transplant recipients. To determine the usefulness of surveillance endomyocardial biopsy, 176 biopsies were reviewed from 12 patients, aged 0.5-16 (average 9.7) yr, maintained on cyclosporine, azathioprine and prednisone immunosuppression, and followed 2.8-45.5 (average 26.3) months after cardiac transplantation. Children old enough to cooperate (n = 6) underwent biopsy on nine occasions in the first 6 months after transplantation and quarterly thereafter. Children too young to cooperate (n = 6) underwent biopsy with general anesthesia on four occasions in the first 6 months after transplantation and every 6 months thereafter. Additional biopsies were performed as warranted by symptoms or noninvasive tests. A new episode of acute rejection was present in 13 biopsies (7%); continuing or resolving rejection in 19 others (11%). Remaining biopsies had no evidence of rejection (82 biopsies, 47%), had lymphocytic infiltrates insufficient for diagnosis (47 biopsies, 27%), were inadequate for diagnosis (14 biopsies, 8%), or were consistent with ischemia (1 biopsy, 0.5%). During the first 6 postoperative months, eight of 101 biopsies were positive for rejection, three occurring on routine surveillance biopsy. After 6 months, five of 75 biopsies showed a new episode of rejection, only one occurring on routine surveillance biopsy. Based on this data, it is concluded that: 1) episodes of rejection are relatively uncommon with triple drug immunosuppression; 2) surveillance biopsies in the first 6 months after cardiac transplantation may show unsuspected rejection; and 3) routine surveillance biopsies more than 6 months after cardiac transplantation are unlikely to show rejection in the absence of symptoms or other tests.

Outcome of coronary artery bypass surgery in diabetic transplant candidates.

Insulin-dependent diabetic (IDDM) patients with end-stage renal disease and coronary artery stenoses > or = 75% have a poor prognosis. However, information is lacking on the morbidity and mortality of the coronary artery bypass operation in this group. We studied 30 consecutive IDDM transplant candidates undergoing a bypass operation to determine the incidence of complications and long-term outcome. Perioperative mortality was 3% and the complication rate was 60%. During follow-up, five patients experienced six myocardial infarctions, the majority within six months of operation. Twenty-one patients underwent successful kidney transplantation after the bypass operation. Overall patient survival was 80%, 73%, and 66% at 1, 2 and 4 yr. In summary, the coronary artery bypass procedure in IDDM transplant candidates has a high morbidity, but the long-term outcome is good. Appropriately counseled IDDM transplant candidates with coronary artery disease should be considered for coronary revascularization and subsequent transplantation.

Memory improvement following cardiac transplantation.

Seventeen patients with severe cardiomyopathy underwent neuropsychological evaluation prior to and at least 1 year after successful heart transplantation. Study candidates were screened, and individuals with a history of stroke, cardiac arrest, or medical and neurological conditions which might affect brain function were excluded. Pre-transplant testing revealed normal intelligence and normal attentional, language, and executive abilities but impaired recent memory. Following heart transplant, memory functioning improved significantly, reaching normal levels. Other cognitive abilities remained unchanged. Results suggest that cardiomyopathy is associated with mesial temporal dysfunction, possibly attributable to inadequate or reduced cerebral blood flow and related hypometabolism. This cerebral dysfunction is potentially reversible following successful transplantation, which restores cardiac output and cerebrovascular perfusion.

Early and late airway complications after lung transplantation: incidence and management.

BACKGROUND: Airway anastomosis complications continue to be a source of morbidity for lung transplant recipients. METHODS: This study analyzes incidence, treatment, and follow-up of airway anastomotic complications occurring in 127 consecutive lung transplant airway anastomoses (77 single lung and 25 bilateral sequential lung). Complications were categorized as stenosis (11), granulation tissue (8), infection (7), bronchomalacia (5), or dehiscence (3). Follow-up after treatment ranged from 6 months to 4 years. RESULTS: Nineteen airway anastomosis complications (15.0%) occurred in 18 patients. Telescoping the airway anastomosis reduced the complication rate to 12 of 97 (12.4%), compared with 7 of 30 (23.3%) for omental wrapping, (p = 0.15). Complications developed in 13 of 77 single-lung airway anastomoses (16.9%) versus 6 of 50 bilateral sequential lung recipients (12.0%). Treatment consisted of stenting (9 airway anastomoses), bronchodilation (8), laser debridement (4), rigid bronchoscopic debridement (2), operative revision (2), and growth factor application (2). There was no difference in actuarial survival between patients with or without airway anastomosis complications (p = 1.0). CONCLUSIONS: Airway anastomosis complications can be successfully managed in the immediate or late postoperative period with good outcome up to 4 years after intervention.

Surgical management of ventricular tachycardia.

BACKGROUND: Ventricular tachyarrhythmias are the leading cause of death from coronary artery disease. A small percentage of these arrhythmias originate in chronically ischemic myocardium, rather than acutely ischemic myocardium, and can be refractory to medical management. Epicardial mapping and focal cryoablation of foci demonstrating early activation may provide definitive therapy when pharmacologic management fails. We report a series of 42 consecutive patients with refractory ventricular tachycardia (VT) who were treated with open epicardial mapping and focal cryoablation after pharmacologic management failed. METHODS: We retrospectively reviewed the records of patients who underwent surgical treatment of malignant VT. For patients not recently seen in the clinic, we conducted telephone interviews. At the time of operation, epicardial mapping was performed to locate foci of early electrical activation. These foci were then cryoablated, using 2-minute applications of liquid nitrogen-cooled probes. All patients underwent postoperative electrophysiologic studies to test for inducible VT. RESULTS: Of these 42 patients, 34 (81%) were male, 8 (19%) female. Average age was 62.9 +/- 10.6 years; ejection fraction, 0.20 (range, 0.04 to 0.50); and number of foci ablated, 2.1 +/- 1.1 (range, 1 to 6). At the time of cryoablation, all patients underwent additional procedures, including aneurysmectomy, coronary artery bypass, or valve replacement. The 30-day operative mortality was 9.5% (4 of 42). Of the 38 survivors, 36 (94.7%) were clinically free of VT; the remaining 2 had spontaneous or inducible VT. CONCLUSIONS: Open cryoablation of foci propagating VT appears to be safe and effective. It may be the most definitive treatment for malignant VT.

Heart transplantation for patients over age 60.

As the proportion of people over age 60 in our society continues to rise, so does the number of potential heart transplant candidates. Advanced recipient age, however, has long been used as an exclusion criterion for transplantation, though the upper age limit remains poorly defined. The purpose of our study was to analyze the outcomes of 31 heart transplant recipients over age 60 at our institution. They were followed with regard to early and late morbidity and mortality. Mean follow-up time was 50 months. The 1- and 5-yr survival rates were 90% and 85%. These rates were not significantly different compared with younger (age 18 to 59) recipients transplanted in the same time period. The older recipients more frequently developed osteoporotic changes as well as cutaneous and visceral malignancies, but had infrequent rejection episodes. Overall, heart transplantation is safe and effective for patients over age 60 with end-stage congestive heart failure. Both 1- and 5-yr survival rates are well within the acceptable range and do not differ significantly from younger recipients. Individualized immunosuppression might help reduce the incidence of malignancy in older recipients, but further studies are needed. Matching donor and recipient age would make the best use of available organs.

Noninvasive diagnosis of cardiac allograft rejection in an orthotopic canine model.

BACKGROUND: A decline in the R wave voltage obtained from surface electrocardiograms once correlated with cardiac allograft rejection. With cyclosporine therapy, however, these electrocardiographic findings became inconsistent, occurring only during severe rejection episodes. Despite cyclosporine use, intramyocardial unipolar peak-to-peak amplitudes obtained from plunge electrodes are reported to be highly sensitive and specific for diagnosing rejection. These reports are based on heterotopic grafts, which atrophy over time, making long-term voltage changes during rejection difficult to interpret. The purpose of this study was to use analysis of unipolar peak-to-peak amplitudes as a prospective monitoring tool for diagnosing orthotopic cardiac allograft rejection. METHODS: Ten adult mongrel dogs underwent orthotopic heart transplantation with the attachment of four intramyocardial leads. The unipolar peak-to-peak amplitudes were measured daily and compared with endomyocardial biopsy results. RESULTS: We found that intramyocardial unipolar peak-to-peak amplitude analysis had a sensitivity and a specificity of 100% for diagnosing rejection. We also found that as the number of myocardial leads increased, the sensitivity of detecting rejection also increased. CONCLUSIONS: We conclude that unipolar peak-to-peak amplitude analysis is an accurate noninvasive means for early detection of cardiac allograft rejection in an orthotopic model. Its success should allow less frequent, more selective use of endomyocardial biopsy.

"Incisura" of the ascending aorta and vascular pedicle width in the cardiac transplant patient.

BACKGROUND: The purpose of this study was to evaluate three findings in cardiac transplant patients: the appearance, etiology, and incidence of "incisura" (a characteristic indentation) of the ascending aorta; the vascular pedicle width, which usually appears enlarged on standard chest radiographs; and clearing of the retrosternal clear space. MATERIAL: Two hundred sixty-one cardiac transplantations were performed at the University of Minnesota before December 31, 1992. The appearance, etiology, and incidence of an incisura were studied; the vascular pedicle width was measured; and the rate of clearing of the retrosternal clear space was determined. RESULTS: Forty-six percent of the patients whose ascending aorta could be visualized on the lateral chest radiogram showed an incisura. Approximately one third of the patients showed continued opacification of the retrosternal space postoperatively. The width of the vascular pedicle in this series of cardiac transplant patients measured 60.9 +/- 22.8 mm (standard deviation, 11.4 mm), in comparison to a normal of 48 +/- 5.0 mm. CONCLUSIONS: An incisura of the ascending aorta and the widened vascular pedicle are normal postoperative chest radiographic findings in cardiac transplant patients and should not be misconstrued as abnormalities.

Mycoplasma hominis infections occurring in cardiovascular surgical patients.

BACKGROUND: Postoperative Mycoplasma hominis sternal would or mediastinal infections are uncommon and difficult to diagnose. Atypical growth characteristics in routine bacterial culture, and the inability to demonstrate the organism on Gram stain, lead to delayed diagnosis of M hominis infections and increased morbidity. METHODS: Postoperative purulent would drainage or acute mediastinitis caused by M hominis developed in 3 cardiovascular surgery patients. These patients were considered along with 9 patients previously reported in the literature. RESULTS: Operative findings included moderately thick, gray purulent fluid with the degree of tissue necrosis related to duration of infection. Intraoperative Gram stain of wound or mediastinal drainage demonstrated no microorganisms, and initial bacterial cultures did not reveal microbial growth. After an average of 4.5 days of culture, minute translucent colonies of M hominis were identified. The institution of appropriate antimycoplasma therapy (doxycycline and clindamycin) was associated with clinical or microbiological cure in all patients. Sternal wound complications developed in 3 patients, and a chronic infection developed in 1 patient. CONCLUSIONS: Empiric therapy for M hominis infection should be considered in patients with mediastinitis or a sternal wound infection in which organisms are not observed on Gram stain and are not readily cultured.

Adjunctive coronary endarterectomy: improved safety in modern cardiac surgery.

BACKGROUND: Advances in cardiac surgery have led to an improved safety record for coronary endarterectomy. METHODS: We retrospectively reviewed the cases of 64 patients who underwent adjunctive coronary endarterectomy between August 1988 and February 1992. There were 44 men, and the mean age was 65 years. Forty-one patients (64%) had sustained a previous infarction. Overall, endarterectomy was performed on 76 vessels, and the right coronary system was involved in 46 (61%). RESULTS: The postoperative infarction rate was 5%. Incomplete occlusion ( < 90% stenosis) of the endarterectomized vessel significantly increased the risk of infarction (p < 0.05). There were two early deaths (3%). The mean follow-up was 46 months. Clinically, 91% of the survivors were angina free, and 80% had no symptoms of heart failure at the time of follow-up. Left ventricular function had improved in 36% of those restudied (5/14). A total of 17 recatheterizations were done at a mean interval of 19 months after operation. The endarterectomy graft patency rate was 80% (16/20) compared with 78% (28/36) for conventional grafts ( p = not significant). The actuarial survival rates were 89% and 71% at 1 year and 5 years, respectively. A history of previous infarction was significantly associated with higher long-term mortality (p < 0.02). CONCLUSIONS: Overall, these results demonstrate that in modern cardiac surgery, coronary endarterectomy is safer than previously thought and can be used effectively to achieve complete revascularization in selected patients.

A model of unilateral pulmonary lobar transplantation.

Unilateral lung transplantation has become an accepted treatment for patients with end-stage pulmonary disease. Donor shortage, however, is a major limitation, with up to 87% of patients dying of their pulmonary disease while awaiting transplantation. This is especially true in neonatal and pediatric patient populations. The use of organ segments from cadaveric or living donors may provide a solution. The purpose of this study, therefore, was to evaluate the function and hemodynamic response to pulmonary lobar transplantation using a swine model. Five transplants were performed for acute study, while 10 were performed for 6-week survival. The left lower lobe was harvested from a 70- to 75-kg donor animal. The lobe was then transplanted into a 20 to 25-kg recipient following left pneumonectomy. Graft function was determined by pulmonary arterial and venous blood gas analysis. Cardiac output, pulmonary pressure, and pulmonary vascular resistance were measured under two experimental conditions: (1) baseline and (2) with the right pulmonary artery occluded, forcing the entire cardiac output through the lobar graft. All grafts showed excellent acute and long-term function with regard to gas exchange. The lobar grafts, however, were characterized by high pulmonary vascular resistance both acutely and 6 weeks post-transplant. Contralateral pulmonary artery occlusion resulted in hemodynamic instability and right heart failure. No animal was able to be solely supported by the lobar transplant for more than one hour. These results have prompted a bilateral lobar transplant model and current studies are in progress.