Modified Norwood operation for hypoplastic left heart syndrome

BACKGROUND

We examined early results in infants with hypoplastic left heart syndrome undergoing the Norwood operation with perioperative use of inhaled nitric oxide and application of extracorporeal membrane oxygenation.

METHODS

Medical records were reviewed retrospectively.

RESULTS

Between April 1997 and March 2001, 50 infants underwent a modified Norwood operation for hypoplastic left heart syndrome. Mean age at operation was 7.5 +/- 5.7 days, and mean weight was 3.1 +/- 0.5 kg. Five infants had a delayed operation because of sepsis. The mean diameter of the ascending aorta by echocardiography was 3.6 +/- 1.8 mm. Ductal cannulation was used to establish cardiopulmonary bypass in all patients. Mean circulatory arrest time was 39.4 +/- 4.8 minutes. The size of the pulmonary-systemic shunt was 3.0 mm in 6 infants, 3.5 mm in 37, and 4.0 mm in 7. Infants with persistent hypoxia (partial pressure of oxygen < 30 mm Hg) received nitric oxide after they were weaned from cardiopulmonary bypass. Extracorporeal membrane oxygenation was initiated in 8 infants in the pediatric intensive care unit primarily for low cardiac output and in 8 in the operating room because of the inability to separate them from cardiopulmonary bypass. The 30-day mortality rate was 22% (11 of 50 patients), and the hospital mortality rate was 32% (16 of 50 patients). Mean follow-up was 17 months. Ten patients (20%) underwent stage-two repair, with one operative death. One survivor had a Fontan procedure, and 2 underwent heart transplantation, with one death.

CONCLUSIONS

Early application of extracorporeal membrane oxygenation for hemodynamic instability and selective use of nitric oxide for persistent hypoxia in the immediate postoperative period may improve survival of patients with hypoplastic left heart syndrome. Renal failure requiring hemofiltration during extracorporeal membrane oxygenation (p < 0.05) and cardiopulmonary arrest in the pediatric intensive care unit (p < 0.05) were predictors of hospital mortality.

Extracorporeal membrane oxygenation in children after repair of congenital cardiac lesions

BACKGROUND

The purpose of this study was to review our experience in the early application of extracorporeal membrane oxygenation (ECMO) in patients requiring mechanical assistance after cardiac surgical procedures.

METHODS

The hospital records of all children requiring ECMO after cardiac operation were retrospectively reviewed, and an analysis of variables affecting survival was performed.

RESULTS

Fifty pediatric patients between May 1997 and October 2000 required ECMO for cardiopulmonary support after cardiac operation. Patients ranged in age from 1 day to 11 years (median age, 40 days). Forty-eight patients underwent repair of congenital cardiac lesions and 2 were included after receiving a heart transplant. Twenty-two children could not be weaned from cardiopulmonary bypass and were placed on ECMO in the operating room for circulatory support. Of the 28 children who required ECMO in the intensive care unit, 10 had ECMO instituted after cardiopulmonary arrest (mean cardiopulmonary resuscitation time 42 minutes; range, 5 to 110 minutes). In infants with single-ventricle physiology, survival to discharge was 61% (11 of 18 patients) as compared with 43% (14 of 32 patients) in those with biventricular physiology. Thirty of the 50 patients (60%) were successfully weaned from ECMO, of which 25 (83%) were discharged home. Overall survival to discharge in the entire cohort was 50%. Extracorporeal membrane oxygenation support greater than 72 hours was a grave prognostic indicator. Overall survival in this group was 36% (9 of 25 patients) compared with 56% (14 of 25 patients) in those with ECMO support less than 72 hours (p < 0.05). Univariate analysis revealed the presence of renal failure, extended periods of circulatory support, and a prolonged period of cardiopulmonary resuscitation as risk factors for mortality. The presence of shunt-dependent flow, operative procedure, and institution of ECMO in the intensive care unit did not alter survival.

CONCLUSIONS

Extracorporeal membrane oxygenation provides effective support for postoperative cardiac and pulmonary failure refractory to medical management. Early institution of ECMO may decrease the incidence of cardiac arrest and end-organ damage, thus increasing survival in these critically ill patients.

Penetrating injury to the heart requiring cardiopulmonary bypass: a case study

Penetrating wounds to the heart represent a significant surgical challenge because of their unique clinical course and the need for emergent operative care. This operative care, which may include cardiopulmonary bypass (CPB), must be initiated in a prompt yet careful fashion to optimize outcome, while minimizing morbidity. Trauma, because of its unpredictable and non-routine nature, may present many challenges to the perfusionist in an attempt to anticipate surgical needs and requirements. In this case report, we describe the successful surgical repair of a cardiac nail gun injury, as well as strategies we feel are essential for the safe, successful, and timely application of emergent CPB.

Mitral valve replacement and endocavitary patch repair for a giant left ventricular pseudoaneurysm

We present a case of a giant inferior left ventricular (LV) wall pseudoaneurysm. The patient had New York Heart Association class IV heart failure due to severe mitral valve regurgitation and poor LV function. Our operative approach included right thoracotomy, excision of the mitral valve, and patch repair of the pseudoaneurysm neck from inside of the dilated LV cavity followed by mitral valve replacement. Surgery was performed without aortic cross-clamping on a normothermic perfused beating heart. The patient had an uncomplicated cardiac recovery and is doing well 15 months after surgery.

Effects of human tissue plasminogen gene transfer on allograft coronary atherosclerosis

BACKGROUND

Transplant coronary atherosclerosis is a major limiting factor to successful long-term cardiac transplantation. The depletion of tissue plasminogen activator (tPA) in the arteriolar smooth muscle cells has been associated with a higher incidence of accelerated graft atherosclerosis. In vivo overexpression of tPA may inhibit accelerated graft atherosclerosis and improve the long-term results of heart transplantation. We evaluated the feasibility, distribution, and effects of intracoronary transfer of the human tPA (htPA) gene in a rabbit heterotopic cardiac transplant model, using a novel cationic liposome compound designed for improved delivery to vascular endothelium.

METHODS

Human tPA cDNA under the control of the SV40 promoter (100 microg) was complexed with the novel cationic liposome (+/-)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propanaminium bromide (GAP: DLRIE) (50 microg), and delivered ex vivo to the donor heart by slow intracoronary infusion. Control hearts received an "empty" liposome preparation. Grafts were then implanted into recipient rabbits in the heterotopic cervical position. For the analysis of gene expression, beating donor hearts were collected at 4 days. To examine the effects of htPA expression on graft atherosclerosis, animals received a 0.5% cholesterol diet for 30 days posttransplant, as well as 10 mg/kg cyclosporine A daily. Beating hearts were collected at 30 days posttransplant and analyzed for the development of transplant atherosclerosis by image analysis.

RESULTS

Northern blot analysis for the htPA messenger RNA (mRNA) transcripts showed significantly higher counts in hearts receiving the htPA gene as compared to controls. The distribution of these transcripts favored the left ventricle (LV) and septal regions over the right ventricle (RV). Scintillation analysis of specimens stained by immunoflourescence showed expression of htPA throughout the perivascular myocardium that was significantly higher in grafts transduced with the htPA gene than in control or native hearts. Expression in the vascular wall was also significantly enhanced. Scintillation counts per x 200 field were 262 +/- 145 in htPA-transduced hearts and 20 +/- 27 in controls (p = 0.001), and mean luminescence was 83.7 +/- 12.5 in htPA-transduced hearts and 62.9 +/- 12.8 in controls (p = 0.01). Intimal hyperplasia was assessed by mean percent luminal stenosis in small- and medium-sized arteries and was 31.12 +/- 23.5% in htPA-transduced hearts and 86.59 +/- 17.5% in control hearts (p < 0.0001). These results demonstrate that expression of the htPA gene can be induced by ex vivo intracoronary gene transfer at the time of allograft preservation. Liposome-mediated delivery of the htPA gene at the time of transplantation results in significant early transgene expression, and significantly inhibits the development of graft coronary atherosclerosis.

Percutaneous stent placement as treatment for an infant with superior vena cava syndrome

The percutaneous use of stents for the treatment of superior vena cava (SVC) syndrome is well described in the adult population. We report the successful use of intravascular stents to treat an infant with severe SVC syndrome.

Structural abnormalities of great arterial walls in congenital heart disease: light and electron microscopic analyses

BACKGROUND

Great arteries in congenital heart disease (CHD) may dilate, become aneurysmal, or rupture. Little is known about medial abnormalities in these arterial walls. Accordingly, we studied 18 types of CHD in patients from neonates to older adults.

METHODS AND RESULTS

Intraoperative biopsies from ascending aorta, paracoarctation aorta, truncus arteriosus, and pulmonary trunk in 86 patients were supplemented by 16 necropsy specimens. The 102 patients were 3 weeks to 81 years old (average, 32+/-6 years). Biopsies were examined by light (LM) and electron (EM) microscopy; necropsy specimens by LM. Positive aortic controls were from 15 Marfan patients. Negative aortic controls were from 11 coronary artery disease patients and 1 transplant donor. Nine biopsies from acquired trileaflet aortic stenosis were compared with biopsies from bicuspid aortic stenosis. Negative pulmonary trunk controls were from 7 coronary artery disease patients. A grading system consisted of negative controls and grades 1, 2, and 3 (positive controls) based on LM and EM examination of medial constituents.

CONCLUSIONS

Medial abnormalities in ascending aorta, paracoarctation aorta, truncus arteriosus, and pulmonary trunk were prevalent in patients with a variety of forms of CHD encompassing a wide age range. Aortic abnormalities may predispose to dilatation, aneurysm, and rupture. Pulmonary trunk abnormalities may predispose to dilatation and aneurysm; hypertensive aneurysms may rupture. Pivotal questions are whether these abnormalities are inherent or acquired, whether CHD plays a causal or facilitating role, and whether genetic determinants are operative.

Molecular heterogeneity of protein kinase C expression in human ventricle

OBJECTIVE

Although activation of protein kinase C (PKC) modulates the function of normal cardiac myocytes and likely plays a role in the pathogenesis of cardiomyopathic disease states, the molecular basis of PKC expression in human ventricle has not been examined in detail.

METHODS

We have performed Western analysis and immunohistochemistry on explanted human cardiac tissue from nondiseased and diseased specimens using isoform-specific antibodies directed against all known PKC isozymes.

RESULTS

In homogenates from left and right ventricle, all isoforms except PKC-gamma and theta were detected by immunoblotting, with confirmation using a second antibody directed against a different epitope when possible. For PKC-betaII, delta, and epsilon, data indicated that these isoforms were variably phosphorylated in vivo, resulting in multiple bands during immunoblotting. Because of potential antibody cross-reactivity, reverse transcriptase polymerase chain reaction (RT-PCR) was performed which confirmed expression of PKC-alpha, betaI, and zeta. Immunohistochemistry demonstrated that all isoforms detected in ventricular homogenate by Western analysis could be localized to cardiac myocytes. From a methodologic standpoint, significant degradation of PKC isoforms could be demonstrated when samples were either frozen or allowed to remain at room temperature, compared to immediate subcellular fractionation.

CONCLUSIONS

These findings indicate that the PKC expression in human ventricular myocytes is remarkably diverse, with multiple conventional, novel, and atypical isoforms present, and highlight the importance of sample preparation in comparative studies of PKC isoform expression.

Long-lasting improvement after septal myectomy for hypertrophic obstructive cardiomyopathy

BACKGROUND

The most effective treatment of symptomatic patients with hypertrophic obstructive cardiomyopathy is still disputed. Treatment options include medical therapy, pacemaker insertion, percutaneous transluminal septal myocardial ablation, mitral valve replacement, and surgical resection of obstructing muscle. The long-term results of the various treatment options are not well defined. We aimed to demonstrate that septal myectomy is efficacious in reducing or abolishing left ventricular outflow tract gradient and leads to long-lasting symptomatic improvement in most patients.

METHODS

Twenty-two consecutive patients had septal myectomy between 1981 and the present. Their records were reviewed to document the details of their preoperative status, hospital course, their subsequent clinical outcome, and current status.

RESULTS

Mean age at operation was 31.3 years. Preoperatively all patients were disabled by typical symptoms despite aggressive medical treatment. Mean resting gradient was 78 mm Hg. Nine patients required simultaneous associated cardiac procedures. There were no perioperative deaths and minimal morbidity. Two patients died at 6 and 9 years postoperatively of congestive heart failure and arrhythmias. Long-term survivors have been followed up for a mean of 6.6 years. Currently all have minimal or no symptoms. The mean resting gradient was 12 mm Hg. No patient has required reoperation for residual obstruction.

CONCLUSIONS

Septal myectomy reduces or abolishes left ventricular outflow tract gradient in hypertrophic obstructive cardiomyopathy. Myectomy provides long-lasting symptomatic improvement in most patients. The clinical status of patients late postoperatively can be affected by arrhythmias and myocardial dysfunction.

Left Internal Mammary Artery Graft Retransplantation from the Recipient to the Donor Heart: A Case Report

A case of heart transplantation with concomitant coronary artery bypass graft is reported. The patient was an alternate transplant list candidate with a history of bilateral below-knee amputation and 2 previous myocardial revascularization procedures. The previously used and patent left internal mammary artery graft was successfully removed and retransplanted from the recipient to the donor heart.

Left internal mammary artery graft retransplantation from the recipient to the donor heart: a case report

A case of heart transplantation with concomitant coronary artery bypass graft is reported. The patient was an alternate transplant list candidate with a history of bilateral below-knee amputation and 2 previous myocardial revascularization procedures. The previously used and patent left internal mammary artery graft was successfully removed and retransplanted from the recipient to the donor heart.

Longitudinal analysis of fibroblast growth factor expression after transplantation and association with severity of cardiac allograft vasculopathy

BACKGROUND

Vascular smooth muscle cell growth factors are postulated to contribute to cardiac allograft vasculopathy (CAV). Few data quantitatively address the timing, location, or stimuli for growth factor expression and relationship to CAV.

METHODS AND RESULTS

Acidic fibroblast growth factor (aFGF) mRNA expression was determined in serial endomyocardial biopsies during the first year after transplantation. Patients with high levels of aFGF mRNA and elevations after the early posttransplant period had significantly more severe CAV than patients with low aFGF and no late elevations.

CONCLUSIONS

Parenchymal aFGF expression varies between patients and in the same patient over time and correlates with development of CAV.

Prospective comparison of radiologic, thoracoscopic, and pathologic staging in patients with early non-small cell lung cancer

BACKGROUND

More accurate staging at the time of initial presentation could improve design of clinical trials and avoid inappropriate surgical decisions in individual patients. Preresection staging of patients with non-small cell lung cancer (NSCLC) is not straightforward, especially in patients with negative mediastinal nodes. The purpose of this study was to compare the results of radiologic, thoracoscopic, and pathologic staging in patients with NSCLC and negative mediastinoscopy.

METHODS

All patients with NSCLC underwent computed tomographic (CT) scanning before surgical staging with mediastinoscopy. Patients with negative mediastinoscopy then underwent thoracoscopic staging with examination of pleural surfaces, and identification of T (visceral and parietal pleural invasion, sampling of pleural fluid, and pleural lavage) and N (intraparenchymal and inferior mediastinal nodal sampling, if possible) stage descriptors before resection.

RESULTS

Thoracoscopy was more accurate than CT scanning in the staging of 50 patients with early lung cancer (stages IA, IB, IIA, and IIB), especially as regards T stage. Further, thoracoscopic examination ruled out malignant pleural effusions in 7 (14%) patients with radiologically obvious effusions, and identified radiologically silent malignant pleural effusions in 3 (6%) patients. Chest wall invasion was accurately identified at thoracoscopy in most patients. Finally, 3 patients with T1 lower lobe lesions and negative mediastinoscopy were found to have involvement of inferior mediastinal nodes (level 8 or 9) at thoracoscopy. However, thoracoscopy did not allow sampling of aortopulmonary window nodes in some patients with bulky left upper lobe lesions.

CONCLUSIONS

Errors in thoracoscopic staging resulted in no inappropriate operations. However, errors in CT staging would have resulted in operations unlikely to help the patients, or would have inappropriately excluded patients from surgery. Thoracoscopic staging was more accurate than CT staging in this cohort of patients with NSCLC and negative mediastinoscopy.

Staged surgical approach to neonates with aortic obstruction and single-ventricle physiology

BACKGROUND

The surgical management of neonatal systemic outflow obstruction and complex single ventricle pathology is variable.

METHODS

In 15 neonates (12 boys and 3 girls) with complex forms of single-ventricle pathology and aortic coarctation or interruption, an initial strategy of banding the pulmonary artery and repair of the obstruction from a left thoracotomy was undertaken.

RESULTS

The median age at operation was 6 days (range 2 to 33 days) and the median weight was 3.3 kg (range 2 to 4.6 kg). There were no early deaths and one late death after the initial surgical palliation. Of the 14 survivors, 8 have undergone a bidirectional cavopulmonary anastomosis. The median age for bidirectional Glenn was 9.75 months (range 3.5 to 26 months). Seven infants have required Damus-Kaye-Stansel reconstruction for subaortic obstruction (one early death). The median age of the Damus-Kaye-Stansel procedure was 4 months (range 3 weeks to 9 months). Thirteen of 15 patients (87%) are alive and 6 have proceeded to a Fontan operation (median follow-up 68 months). A single failing Fontan required takedown to bidirectional Glenn and central shunt.

CONCLUSIONS

Our experience suggests that this high-risk subgroup of neonates with aortic obstruction and single-ventricle pathophysiology is safely managed by initial pulmonary artery banding palliation and repair of aortic obstruction. This strategy, careful surveillance, and early relief of subaortic stenosis can maintain acceptable anatomy and hemodynamics for later bidirectional Glenn and Fontan procedures.

The utility of exercise testing after cardiac transplantation in older patients

BACKGROUND

The criteria for cardiac transplantation recipient selection, including the appropriate recipient upper age limit, continue to expand with an increasing number of recipients greater than 60 years of age. While others have reported their transplant experience in older recipients in terms of quality of life assessment, we have examined the role of exercise cardiopulmonary testing post-transplantation in older cardiac transplant recipients.

METHODS

We reviewed inpatient and outpatient charts of 28 patients 60 years of age or older who underwent orthotopic heart transplantation at Vanderbilt University Medical Center.

RESULTS

In this population, perioperative mortality of 7.1% and Kaplan-Meier survival at 1 and 5 years of 89 and 77%, respectively, were similar to the institutional 1-year (89%) and 5-year (75%) survival among younger adult transplant recipients. Exercise cardiopulmonary testing results were available in 22/25 patients surviving greater than 1 year. Both peak oxygen consumption and percentage of maximum VO2 were significantly greater among patients reporting NYHA Class 1 or 2 functional status, in comparison with those NYHA Class 3 or greater.

CONCLUSION

Following cardiac transplantation, survival of patients greater than 60 years of age is equivalent to that of younger patients at our institution. Exercise testing provides an objective measure of performance and correlates with subjective status following heart transplantation. Most patients demonstrate good functional status, with minimal symptoms and good exercise capacity. These results, although retrospective, suggest that cardiac transplantation remains a reasonable therapeutic option for patients greater than 60 years of age with end-stage cardiomyopathy.

Benefits of early surgical repair in fixed subaortic stenosis

OBJECTIVES

We sought to determine whether early resection can improve outcome in fixed subaortic stenosis.

BACKGROUND

The diagnosis of subaortic stenosis (SAS) is often made before significant gradients occur. Whereas resection is the accepted treatment, it remains uncertain whether surgical intervention at this early stage can reduce the incidence of recurrence or influence the progression of aortic valve damage.

METHODS

Follow-up was available for 75 of 83 consecutive patients operated on for fixed SAS; the average duration of follow-up was 6.7 years. The lesion was discrete in 68 patients (91%) and of a tunnel type in 7, with associated ventricular septal defect in 28 (37%). All underwent transaortic resection.

RESULTS

There were no deaths. There were 18 recurrences of SAS in 15 patients (20%). Thirteen patients (17%) underwent 17 reoperations for recurrence or aortic valve disease. The cumulative hazard of recurrence was 8.9%, 16.1% and 29.4% +/- 2.3% (mean +/- SEM), and the hazard of events, including recurrence and reoperation, was 9.2%, 18.4% and 35.1% +/- 3.5% at 2, 5 and 10 years, respectively. Residual end-operative left ventricular outflow tract (LVOT) gradients (> 10 mm Hg, n = 8) and tunnel lesions were univariate predictors of recurrence (p = 0.0006 and p = 0.003, respectively). Multivariate predictors included higher preoperative LVOT gradient (p < 10(-4)) and younger patient age (p = 0.002). Only two recurrences (0.87 per 100 patient-years of follow-up) were noted in patients with a preoperative peak LVOT gradient < or = 40 mm Hg (n = 40), whereas higher gradients (n = 35) were associated with a greater than sevenfold recurrence rate (6.45 events per 100 patient-years, p = 0.002). The aortic valve required concomitant repair in 17 cases in the high gradient group (48.6%) but in only 8 in the low gradient group (20%, p = 0.018). Despite relief of the obstruction, progressive aortic regurgitation was noted at follow-up after 14 procedures in the high gradient group (40%) but after only 5 procedures in the low gradient group (12.5%, p = 0.014).

CONCLUSIONS

The data suggest that surgical resection of fixed subaortic stenosis before the development of a significant (> 40 mm Hg) outflow tract gradient may prevent recurrence, reoperation and secondary progressive aortic valve disease.

Intracoronary adenovirus-mediated transfer of immunosuppressive cytokine genes prolongs allograft survival

BACKGROUND

Intracoronary transfer and expression of recombinant genes in the intact heart is now feasible. In the transplant setting, local modulation of host immune responses by a genetically modified allograft may offer an attractive alternative to systemic immunosuppression.

METHODS

We tested the efficacy and in vivo effect of intracoronary transfer of two immunosuppressive cytokine genes. First-generation E1-deleted adenoviral vectors expressing the Epstein-Barr virus interleukin-10 (AdSvIL10) or human transforming growth factor--beta 1 (AdCMVTGF-beta) were used. Rabbit cardiac allografts were transduced during cold preservation by slow (1 ml/min) intracoronary infusion of 10(10) pfu/gm diluted viral vectors and then implanted heterotopically. Controls included E1-deleted adenovirus (Ad5dI434) and AdCMVLacZ. Beating allografts were collected on day 4 for analysis of gene transfer efficacy and distribution. Additional grafts were used for evaluation of alloreactivity (n = 34).

RESULTS

Mean allograft viral uptake was 81% (up to 91%). Polymerase chain reactions and reverse transcription-polymerase chain reactions confirmed the presence and expression of both genes in the grafts. beta-Galactosidase staining in AdCMVLacZ-infected grafts demonstrated efficient gene expression, which was highest (100%) in subepicardial regions. More homogeneous transmyocardial distribution of the transgene (in 25% to 40% of cells) could be achieved by pulsatile slow delivery. Allograft survival was 6.9 +/- 0.9 days in controls (n = 12), 11.1 +/- 1.7 days in AdCMVTGF-beta-infected grafts (n = 11, p < 10(-4)), and 11.2 +/- 3 days in AdSvIL10-infected grafts (n = 11, p < 10(-4)). Histologic scores (blinded) showed significantly (p < 0.005) higher regression coefficients for rejection in controls compared with both cytokine-transduced groups. Perioperative administration of cyclosporine A (INN: ciclosporin) to recipients had no effect on survival of AdCMVTGF-beta-infected grafts but reduced survival of AdSvIL10-infected grafts.

CONCLUSIONS

Intracoronary gene transfer of immunosuppressive cytokines to cardiac allografts is efficient and effectively prolongs graft survival. Vectors that would induce long-term expression of such genes may make this approach clinically applicable.

Multiple left heart obstructions (Shone's anomaly) with mitral valve involvement: long-term surgical outcome

BACKGROUND

The outcome of children with multilevel left heart obstructions (Shone's anomaly) is generally poor. Literature is scarce, consisting mainly of case reports. The mitral disease may be the predominant factor affecting outcome.

METHODS

Surgical results in 19 consecutive patients are presented, with a median follow-up of 8 years. Mitral stenosis was present in all, with parachute deformity in 12 patients. Supramitral rings were found in 9 patients. Other features included subaortic stenosis (15 patients), valvar aortic stenosis (9), bicuspid aortic valve (16), and coarctation (13 patients). The patients underwent 46 surgical procedures, including 18 mitral operations (9 replacements, 9 repairs).

RESULTS

There were three in-hospital (16%) and two late (10.5%) deaths. Of the 5 nonsurvivors, 4 patients (80%) had predominant mitral disease and moderate to severe pulmonary hypertension, versus 4 (28.5%) and 5 (36%) survivors, respectively (p = not significant). Valve repair was the final procedure in 9 survivors. The other 5 patients had repeated valve replacements (1), aortoventriculoplasty with valve replacements (2), or no mitral operation (2). Freedom from mitral reoperation was 78% (7 of 9 patients) after repair procedures and 43% (3 of 7 patients) after replacement. At follow-up, 10 patients (71.4%) are in New York Heart Association functional class I and the other 4 in class II and III. Six (43%) await reoperation due to recurrent aortic (4) or subaortic (1) stenosis and recoarctation (2). Echocardiography reveals mild mitral stenosis or regurgitation in 3 patients after repair (33%). Four are considered free of residual disease (21% of all).

CONCLUSIONS

Late outcome in Shone's anomaly seems to correlate with the predominance of mitral valve involvement and the degree of pulmonary hypertension. Valve repair is indicated whenever feasible and should be considered before the occurrence of pulmonary hypertension.

The alternate recipient list for heart transplantation: does it work?

BACKGROUND

One quarter of patients awaiting heart transplantation die while on the waiting list. This is largely due to the shortage of donor organs. The alternate recipient list was created to establish a means by which patients who would otherwise be turned down for heart transplantation solely because of age over 65 or a need for a third heart transplantation can receive organs considered marginal that may otherwise be wasted. The hope is that these patients may achieve improved survival with these substandard hearts than they would achieve with medical therapy alone.

METHODS

Twenty-two patients ages 47 to 71 years (mean 66.7 years) were listed on the alternate recipient list at the University of California at Los Angeles Medical Center from 1991 to 1996. Seventeen patients underwent heart transplantation from the alternate waiting list. The outcome of this group was compared with the outcome of a contemporaneous group of 266 patients ages 18 to 66 years (mean age 52.1 years) from the standard heart transplantation waiting list.

RESULTS

The early mortality rate for the patients in the alternate group was 11.8% (2/ 17). Actuarial survival from time of orthotopic heart transplantation at 6 months and 1 year was the same 74.5% at a mean follow-up was 13.4 months. In comparison, the early mortality rate for the patients on the standard list was 5.6% (15/266), and actuarial survival at 6 months and 1 year was 86.8% and 83.1%, respectively (mean follow-up was 30 months). There was no significant difference in early mortality rate or actuarial survival between the two groups.

CONCLUSION

The alternate recipient list for heart transplantation is a valid and ethical option for patients who would otherwise be denied heart transplantation. It provides these patients with similar early and medium-term outcomes in comparison to patients on the standard list, and organs that may otherwise be wasted are used.

Controlled periadventitial administration of verapamil inhibits neointimal smooth muscle cell proliferation and ameliorates vasomotor abnormalities in experimental vein bypass grafts

OBJECTIVE

Inhibition of early myointimal proliferation may improve longterm patency of vein grafts, but the clinical use of many experimental drugs is limited by systemic toxicity. To determine whether this goal can be achieved by low-dose targeted drug administration, we constructed a polymeric system delivering verapamil and evaluated the effects on local and downstream vein graft morphology, neointimal smooth muscle cell proliferation, and vasomotor function.

METHODS

Ethylene-vinyl acetate polymeric delivery systems were constructed, containing 2% verapamil by weight. These are flexible, biocompatible, and nonbiodegradable matrices, delivering the drug at a rate of 10 micrograms/day. The autologous external jugular vein was used to create a carotid artery bypass graft in hypercholesterolemic (n = 22) rabbits. Verapamil-containing matrices (n = 12) or plain polymers (control, n = 10) were wrapped around the proximal third of the veins after reperfusion. Graft vasomotor function was evaluated and was also compared with function of an additional group of normocholesterolemic vein grafts (n = 8).

RESULTS

Twenty-eight days after grafting, intimal index (intima/media thickness ratio) was 31% lower, neointima/original lumen surface ratio was 26% lower, and residual luminal area was 71% greater (4.00 +/- 1.2 mm2 versus 2.34 +/- 0.9 mm2, all p < 0.01) under verapamil matrices compared with control grafts. Neointimal smooth muscle cell content was reduced from 45.4% to 28.2%, and net neointimal smooth muscle cell thickness was reduced by 47% (30 microns vs 15.8 microns, both p < 0.01). Verapamil-treated segments distal to the matrices also showed significantly lower neointimal smooth muscle cell density and increased lumen size. Sensitivity to serotoin and vasomotor responses to serotonin, norepinephrine, and sodium nitroprusside in distal segments were significantly lower in verapamil-treated grafts than in controls.

CONCLUSIONS

Periadventitial controlled administration of verapamil below 1% of the systemic dose effectively inhibits myointimal hyperplasia in vein grafts. Local polymeric drug delivery may be readily applicable to coronary revascularization operations.

Intracoronary gene transfer of immunosuppressive cytokines to cardiac allografts: method and efficacy of adenovirus-mediated transduction

OBJECTIVE

Allograft-targeted immunosuppressive gene therapy may inhibit recipient immune activation and provide an alternative to systemic immunosuppression. We studied the optimal technique and efficacy of intracoronary gene transfer of viral interleukin-10 and human transforming growth factor-beta 1 in a rabbit model of heterotopic heart transplantation.

METHODS

Replication-defective adenoviral vectors were constructed, expressing viral interleukin-10 (AdSvIL10) or transforming growth factor-beta 1 (AdCMVTGF-beta 1). Intracoronary delivery of vectors was accomplished ex vivo by either bolus injection or slow infusion. The allografts were implanted heterotopically in recipient rabbits and collected 4 days after the operation. Vector dose was 4 x 10(9) to 6 x 10(10) pfu/gm of donor heart. Transfer was confirmed by DNA amplification for both genes. Gene product expression in tissue was quantified by immunoassay and visualized by immunohistochemical staining.

RESULTS

Allograft viral uptake was only 9.9% +/- 2.4% with bolus injection, but increased to 80.5% +/- 6.8% at 1 ml/min infusion rate (p = 5 x 10(-14)). Uptake ratio was not affected by vector quantity or slower infusion rates. Transforming growth factor-beta 1 was consistently detected in allografts infected with AdCMVTGF-beta 1, but not with control adenovirus or AdSvIL10. Expression was proportional to infused vector quantity and reached 10 ng/gm of allograft at infused 10(10) pfu/gm. Transforming growth factor-beta 1 was also detected in recipient's serum at less than 1 ng/ml. Viral interleukin-10 was detected in minor amounts only (< 1 ng/gm) in allografts infected with AdvIL10 up to 5 x 10(10) pfu/gm. Nevertheless, it was detected in recipient serum at concentrations up to 0.4 ng/ml.

CONCLUSIONS

Intracoronary gene transfer of immunosuppressive cytokines to cardiac allografts during cold preservation is feasible. Slow infusion is superior to bolus injection. In vivo effects on allograft rejection remain to be determined.

The Fontan procedure in adults

BACKGROUND

A retrospective clinical study was performed to document the course of adult patients undergoing the Fontan procedure.

METHODS

Between 1982 and 1994, 21 adults aged 18 to 40 years (mean age, 27 +/- 7 years) underwent a Fontan procedure. Anatomic diagnosis was tricuspid atresia in 9, double-inlet left ventricle in 4, and various single ventricles in 8. Four underwent a right atria-right ventricle connection, 13 had a right atria-pulmonary artery connection, and 4 had a lateral-tunnel Fontan. Three of these 4 had a snare-adjustable atrial septal defect. Preoperative risk factors assessed were left ventricular end-diastolic pressure greater than 10 mm Hg, ejection fraction lower than 0.45, mean pulmonary artery pressure higher than 15 mm Hg, transpulmonary gradient greater than 10 mm Hg, pulmonary artery abnormalities, and atrioventricular valve regurgitation. Mean preoperative risk score was 1.6 /-1.1. Mean New York Heart Association class was 2.6 +/- 0.5.

RESULTS

The operative mortality rate was 5% (1/21). Six patients (30%) had a major complication, four being prolonged effusions. One patient was lost to follow-up; the remaining 20 have been followed for a mean of 7.4 +/- 3.8 years. At follow-up, mean New York Heart Association class was 1.7 +/- 0.5. There has been one late death (5%) at 9 2/3 years, which was probably due to ventricular arrhythmia. Three patients (16%) have required and survived reoperation. During follow-up, 7 patients (37%) have had development of atrial arrhythmias requiring medication, and 2 have been treated for ventricular arrhythmias.

CONCLUSIONS

These results indicate that properly selected adults can undergo the Fontan procedure with low morbidity and mortality. However, late-developing arrhythmias, need for reoperation, and decreasing ventricular function are serious problems that mandate careful follow-up.

Unbalanced atrioventricular septal defects

Complete atrial ventricular septal defects (AV canal) generally have right and left valve components equally divided. However, in unbalanced AV canal either right or left ventricle dominance may occur. The spectrum may vary between those readily able to undergo biventricular repair at no increased risk to those requiring a single ventricle approach in cases with severe hypoplasia of the ipsilateral ventricle. The most challenging diagnostic cases fall within the gray area between the two ends of the spectrum, in which one ventricle is not clearly hypoplastic. Diagnostic modalities that are used to evaluate these ventricles include echocardiography and angiographic ventriculography using volume formulae. Magnetic resonance imaging (MRI) has also recently been found to be a useful technique with which further experience is being developed. Once the determination of a single ventricle physiology has been made, early intervention (ie, pulmonary artery banding) to protect both the pulmonary vasculature and the ventricular function is performed. Follow-up with catheterization and bidirectional Glenn should be completed usually by around 4 to 6 months of age. This palliation and subsequent Fontan completion has had good results based largely on two factors: ventricular dominance, left being better than right, and the absence of pulmonary vascular hypertension.

Temporary mechanical support with the BVS 5000 assist device during treatment of acute myocarditis

BACKGROUND

Ventricular support with the BVS 5000 (Abiomed) has been used as temporary circulatory assist for the failing heart. Our purpose is to summarize four cases illustrating the role of mechanical unloading in acute myocarditis.

METHODS

Four patients aged 16- to 33-year old presented with congestive heart failure 4 to 20 days after a flu-like syndrome. All patients were in severe cardiogenic shock +/- renal and liver dysfunction. Ejection fraction ranged from 5% to 26%. Indications for ventricular assist were failure of maximal medical treatment with > or = two inotropes +/- intra-aortic balloon pump. Myocardial biopsy revealed acute myocarditis in three patients and severe edema in one despite a characteristic clinical course. Two patients received immunotherapy with OKT3. Biventricular assist was used in three patients and left ventricular assist only was used in one. Mean support time was 8.3 days (7 to 11).

RESULTS

All patients had recovery of myocardial function and were discharged from the hospital in good condition.

CONCLUSION

The BVS 5000 device provides a safe, simple, and effective method to support the circulation during acute myocarditis. We hypothesize that this may facilitate myocardial recovery by decompressing the distended ventricle. Ventricular assist devices should be used early in the presence of hemodynamic deterioration on maximal medical therapy.

Evidence of improved microvascular perfusion when using antegrade and retrograde cardioplegia

BACKGROUND

The maximum degree of microvascular distribution of cardioplegic solution is considered important to achieve optimum myocardial protection. This study attempts to demonstrate that the addition of retrograde cardioplegia to antegrade cardioplegia improves overall microvascular perfusion.

METHODS

Explanted human hearts (n = 6) were treated with cold cardioplegic arrest and bicaval cardiectomy. Blood cardioplegia (37 degrees C) containing colored microspheres (color A for antegrade, color B for retrograde) was simultaneously infused antegrade at a pressure of 80 mm Hg and retrograde at a pressure of 40 mm Hg for 2 minutes. The ventricular myocardium was then sampled at three sites to determine absolute and relative cardioplegic microvascular flow.

RESULTS

Of the total microvascular capillary flow, 27% to 32% was found to be the contribution of retrogradely delivered cardioplegia.

CONCLUSIONS

Despite being delivered simultaneously and at a lower pressure, retrograde cardioplegia contributed substantially to overall microvascular perfusion. This suggests that antegrade cardioplegia alone does not perfuse all available myocardial capillaries and that the addition of retrograde cardioplegia enhances overall microvascular distribution and perfusion.

Issues in surgical treatment of endocarditis including intraoperative and postoperative management

Patients with infective endocarditis who require surgical intervention can be divided into four separate groups, in order of incidence: (1) patients with underlying acquired or congenital cardiac lesions or valvar abnormalities, (2) patients with preexisting prosthetic valves, (3) patients with nosocomial infections who are immunosuppressed, and (4) older patients with infection risk or patients with indwelling deep venous catheters. The surgical management for these individual groups and for specific valve lesions is discussed, along with illustrative case studies.

Outcomes of patients undergoing transplantation with older donor hearts

BACKGROUND

The limited number of donor hearts relative to the number of waiting recipients is the major determinate of a growing inequity. Although a number of potential options are being vigorously pursued, the most effective immediate solution is to expand acceptance criteria for donor age and medical condition. This report is a review of our early and late results with the use of older donors, including simultaneously "bypassed" donor hearts.

METHODS

Between April 1987 and September 1994, 52 patients received older donor hearts (older than 45 years) with a mean donor age of 51 years. Ten patients in this group received hearts simultaneously bypassed with from 1 to 4 grafts per patient. Donor and recipient age, diagnosis, and HLA match were compared between the older donor group and a contemporaneous younger (younger than 45) donor group (N = 324). Also compared was actuarial survival at up to 5 years of follow-up in addition to graft function, bypass graft patency, infection and rejection incidence at 1 year, and the prevalence of transplant-associated coronary artery disease in the two groups. Echocardiography, coronary angiography, and intravascular coronary ultrasonography were used for this assessment.

RESULTS

One-year actuarial survival was 84% for the older donor group, which included 19 status 1 patients (survival 76%) and 23 status II patients (survival 90%). In the bypassed donor subgroup there was a 60% 1-year actuarial survival with 5 status 1 patients (survival 80%) and 5 status II patients (survival 40%). At 1 year, left ventricular function and the incidence of infection and rejection were equal between these two donor groups. Five-year actuarial survivals were the same between the overall older and younger donor groups. Finally, the development of transplant-associated coronary disease was similar in both groups up to 5 years after transplantation.

CONCLUSIONS

This initial review of heart transplantation with older donor hearts, including bypassed hearts, demonstrates similar early and late survival outcomes as compared with those of a contemporaneous younger donor group. Significantly, there appears to be no difference in the development of transplant-associated coronary artery disease during the follow-up period. The older donor represents a potential immediate increase in the number of suitable hearts for transplantation. Bypassed donor hearts represent a small but potentially significant subgroup that may be safely and effectively used when appropriately matched to the recipient by age and medical condition. Greater experience, particularly with this bypassed group, will help determine optimal donor-to-recipient matching for the future.

Preservation of endothelium-dependent vasodilation with low-potassium University of Wisconsin solution

University of Wisconsin solution has provided excellent myocardial preservation. However, the high potassium content of the currently available University of Wisconsin solution has been implicated in coronary artery endothelial damage. We placed 16 neonatal (age 1 to 3 days) Duroc piglet hearts on an isolated nonworking perfusion circuit. Endothelium-dependent and endothelium-independent vasodilation were tested by measuring coronary blood flow after intracoronary infusion of bradykinin (10(-6) mol/L) and nitroprusside (10(-6) mol/L), respectively. In addition, nitric oxide levels were measured after bradykinin infusion. The hearts were then arrested blindly with either a modified University of Wisconsin solution (group 1; n = 8, K+ = 25 mEq/L) or standard University of Wisconsin solution (group 2; n = 8, K+ = 129 mEq/L) by infusion of cardioplegic solution every 20 minutes for a total of 2 hours. After bradykinin infusion, the mean coronary blood flow increased by 237.1% +/- 14.0% of baseline valves before arrest and by 232.8% +/- 16.0% after arrest in group 1 (p = not significant). As in the first group, the mean coronary blood flow in group 2 increased by 231.1% +/- 13.7% before arrest; however, the increase in mean coronary blood flow after arrest was significantly attenuated (163.3% +/- 12.8%, p < 0.01). The loss of endothelium-dependent coronary blood flow response in group 2 correlated with a decreased capacity to release nitric oxide after arrest (prearrest 8.25 +/- 2.30 nmol/min per gram versus postarrest -2.46 +/- 2.29 nmol/min per gram, p < 0.01). Endothelium-independent vasodilatory response revealed no significant difference between groups before and after arrest. These results suggest that the low-potassium University of Wisconsin solution provides superior protection of the endothelium by preserving the endothelium-dependent vasodilatory response to nitric oxide release.

A comparison of distribution between simultaneously or sequentially delivered antegrade/retrograde blood cardioplegia

Commercially available cardioplegia delivery systems now allow for antegrade (aortic root, coronary ostia, saphenous vein graft) perfusion to occur either sequentially or simultaneous with retrograde (coronary sinus) perfusion. This study was designed to compare the total flow and local distribution of sequential versus simultaneous antegrade/retrograde cardioplegia delivery.

METHODS

Explanted human hearts diagnosed with idiopathic cardiomyopathy underwent a cold cardioplegic arrest and bicaval cardiectomy. Thirty-seven degree centigrade blood cardioplegia containing colored microspheres was then delivered antegrade (red color) at a pressure of 80 mmHg or retrograde (blue color) at a pressure of 40 mmHg. In the sequential group (n = 6), cardioplegia was delivered antegrade and then retrograde for 2 minutes, respectively. For the simultaneous group (n = 6), cardioplegia was delivered both antegrade and retrograde for 2 minutes. The ventricular myocardium was then sampled at 12 representative sites to determine regional cardioplegic flow.

RESULTS

Mean total cardioplegia delivery/minute was 0.69 +/- 0.62 mL/g per minute for sequential cardioplegia, and 0.46 +/- 0.19 mL/g per minute for simultaneous cardioplegia (p > 0.05, NS). At the 12 ventricular sites sampled, mean regional cardioplegic flow (mL/g per min) was in general slightly greater for sequential delivery. However, this was not statistically significant (p > 0.05, NS).

CONCLUSION

The data suggest that there may be a slight advantage in total cardioplegia delivery and regional cardioplegia delivery when using sequential rather than simultaneous cardioplegia delivery. However, this difference was not statistically significant and is likely not of clinical significance. Therefore, we would recommend using either sequential or simultaneous antegrade/retrograde cardioplegia based upon whichever technique facilitates the conduct of the individual operation.

Cardiac gene transfer by intracoronary infusion of adenovirus vector-mediated reporter gene in the transplanted mouse heart

This study introduces a model for intracoronary gene transfer in murine cardiac isografts using adenovirus vectors. This approach may offer an opportunity to modulate alloreactivity after cardiac transplantation. Donor hearts were infected via the coronary arteries with a volume of 10(9) plaque-forming units per milliliter of a recombinant adenovirus containing the beta-galactosidase-encoding gene (Ad.CMVLacZ). In a control group, 200 microliters of normal saline solution was infused. The grafts were stored in 4 degrees C cold saline solution for 15 minutes, then transplanted heterotopically into syngeneic hosts (B10.BR). The grafts were harvested at 3, 7, 15, or 30 days (n = 5 for each group) after transplantation, and beta-galactosidase activity was assessed by histochemical staining (X-gal). All grafts were functioning when harvested. X-gal staining pattern was nonuniform with positive staining appearing in epicardial, myocardial, and endocardial cells, as well as in the vessel walls. The cells permissive to infection consisted predominantly of myocardial cells. The mean total numbers of beta-gal-positive staining cells per slice were 68.7 +/- 27.3 in the 3-day group, 330.4 +/- 53.8 in the 7-day group, 151.3 +/- 48.0 in the 15-day group, and 39.9 +/- 10.8 in the 30-day group, thus peaking in the 7-day group (p < 0.05). Control isografts (n = 5), retrieved at day 30, revealed no staining activity. In conclusion, our model demonstrates that intracoronary gene transfer to the transplanted murine cardiac grafts is feasible at the time of harvest. Adenovirus-mediated gene transfer produces widespread gene expression which, though perhaps transient, does not adversely affect myocardial structure or function. This technology may allow modification of graft immunogenicity in the future through the production of therapeutic proteins sufficient to modulate local immune responses.

Leiomyosarcoma of the vena cava with atrial extension: long-term survival following resection and caval replacement without circulatory arrest

This is a case report of a primary vena cava sarcoma extending to the atrium in a young woman, which was resected. Cardiopulmonary bypass was used, and the cava replaced with ringed Gore-Tex. She remains alive and well more than 3 years after the surgery with no evidence of recurrence.

Can improved microvascular perfusion be achieved by using both antegrade and retrograde cardioplegia?

BACKGROUND

The complete and uniform distribution of cardioplegia to the microvasculature of the heart is considered critical for myocardial protection. This study explores the hypothesis that enhanced microvascular perfusion can be achieved by using both antegrade and retrograde cardioplegia.

METHODS

Infant piglet hearts (n = 15) were arrested with antegrade blood cardioplegia, excised, and fixed with 2.5% glutaraldehyde by retrograde perfusion. Hearts were then perfused retrograde with an inert intracapillary marker (NTB-2). Six of these hearts served as controls (group 1) to anatomically demonstrate the degree of capillary perfusion achieved by the retrograde delivery route. Nine experimental hearts (group 2) underwent a subsequent infusion of antegrade blood cardioplegia to wash out NTB-2 capillaries coperfused by both the antegrade and retrograde delivery techniques. Sections of the left ventricular free wall and anterior-mid interventricular septum were taken and examined by light microscopy at four separate sites (average, 126 capillaries per section).

RESULTS

In control hearts, 91.9% +/- 0.9% of ventricular capillaries and 91.4% +/- 5.8% of septal capillaries were perfused by retrograde cardioplegia. After antegrade blood cardioplegia washed out group 2 hearts, 14.0% +/- 4.1% of capillaries in the ventricle still contained NTB-2, as did 12.5% +/- 5.4% of capillaries in the septum.

CONCLUSIONS

In this experimental model, antegrade blood cardioplegia did not coperfuse (and therefore washout) 12.5% to 14% (p < 0.05) of capillaries perfused by retrograde cardioplegia. This suggests that an additional 12.5% to 14% of capillaries within the myocardium may receive cardioplegia if retrograde cardioplegia is used in addition to antegrade cardioplegia. We conclude that by combining both antegrade and retrograde cardioplegia, there is a potential for enhanced overall microvascular perfusion.

University of Wisconsin solution versus Stanford cardioplegic solution and the development of cardiac allograft vasculopathy

BACKGROUND

University of Wisconsin (intracellular) solution has been shown to offer some distinct benefits of myocardial preservation over Stanford (extracellular) solution, including a more rapid functional recovery, improved adenosine triphosphate preservation, and a tendency for less postoperative inotropic agents. However intracellular solutions with high potassium content have been reported to cause a functional if not structural endothelial injury in laboratory experiments.

METHODS

Because of this information we retrospectively viewed our follow-up angiographic data for the development of the cardiac allograft vasculopathy in a consecutive series of 195 heart transplant recipients. These patients were treated in identical fashion, with the same immunosuppression regimen, except for the type of cardioplegia used--Stanford solution (group I n = 95) and University of Wisconsin solution (group II n = 100).

RESULTS

With a mean follow-up of 24 months after transplantation, a significant difference was seen in the development of cardiac allograft vasculopathy in group II (22%) versus group I (14%, p < 0.03). Although significant differences were observed with univariate analysis with respect to donor age and ischemic time favoring group I and with multivariate statistical analysis with respect to overall rejections favoring group II, the only significant variable for the difference in the development of allograft vasculopathy was University of Wisconsin cardioplegic solution (p < 0.003). A subgroup of 30 patients previously randomized for a functional study comparing the two cardioplegic agents showed a tendency for statistical significance with a freedom from allograft vasculopathy of 93% in group I, as compared with 83% in group II, after 13 months follow-up (p = 0.09). The overall probability of being free of vasculopathy at 24 months was 86% for group I and 70% for group II.

CONCLUSIONS

The data support the conclusion that University of Wisconsin intracellular solution is associated with an increased incidence of vasculopathy versus Stanford solution and warrants investigation for modification of this preservation agent in heart transplantation.

Extracellular and standard University of Wisconsin solutions provide equivalent preservation of myocardial function

The deleterious effect of hyperkalemic cardioplegic solutions on coronary endothelium has been documented and has also been demonstrated with University of Wisconsin solution. We evaluated a new extracellular University of Wisconsin formulation for efficacy in heart preservation. Six neonatal piglet hearts were arrested with and stored in the standard intracellular University of Wisconsin solution (group 1: K+ 125 mEq/L, Na+ 29 mEq/L). Six piglet hearts were preserved for 24 hours with an extracellular University of Wisconsin solution that differed only in the concentrations of potassium and sodium (group 2: K+ 25 mEq/L, Na+ 129 mEq/L). Hearts underwent modified reperfusion with leukocyte-depleted aspartate-glutamate enriched blood cardioplegic solution followed by conversion to a left-sided working mode on a Langendorff circuit with perfusion from a support pig. Stroke work index was calculated at left ventricular end-diastolic pressures of 3, 6, 9, and 12 mm Hg. Sixty minutes after reperfusion, there was no significant difference in stroke work index between group 1 (16.4 +/- 1.9 x 1000 erg/gm) and group 2 (15.3 +/- 2.7 x 1000 erg/gm). There was also no significant difference in high-energy phosphate stores or myocardial water content between the two groups. Extracellular University of Wisconsin solution provides myocardial preservation equivalent to standard University of Wisconsin solution while preventing exposure of coronary endothelium to high levels of potassium, which justifies its use in clinical heart transplantation.

Implantable defibrillators for high-risk patients with heart failure who are awaiting cardiac transplantation

The objective of this study was to assess the operative risk and efficacy of implantable defibrillators for preventing sudden death in patients with heart failure awaiting transplantation. The average waiting time for elective cardiac transplantation is 6 months to 1 year. Sudden cardiac death is the major source of mortality in outpatients in stable condition awaiting cardiac transplantation. The efficacy of implantable defibrillator therapy in this population is not established. We analyzed the operative risk, time to appropriate shock, and sudden death in 15 patients determined to be at high risk of sudden death who were accepted onto the outpatient cardiac transplant waiting list. Nonfatal postoperative complications occurred in two (13%) subjects with epicardial defibrillating lead systems and in none with transvenous lead systems. Defibrillation energies were 16 +/- 2 J versus 24 +/- 2 J with epicardial and transvenous lead systems, respectively. Sudden death free survival until transplantation was 93%. Most of the patients (60%) had an appropriate shock during a mean follow-up of 11 +/- 12 months. The mean time to an appropriate shock was 3 +/- 3 months. Hospital readmission was required in three (20%) subjects to await transplantation on an urgent basis. However, two of these subjects had received appropriate shocks before readmission. In selected patients at high risk for sudden death while on the outpatient cardiac transplant waiting list, the operative risk is low and adequate defibrillation energies can be obtained to allow implantable defibrillator placement. Most subjects will have an appropriate shock as outpatients before transplantation, and sudden death free survival is excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Corticosteroid weaning late after heart transplantation: relation to HLA-DR mismatching and long-term metabolic benefits

BACKGROUND

To avoid the long-term side effects of corticosteroids, corticosteroid-free immunosuppression has been introduced immediately or late (more than 6 months) after heart transplantation. Late corticosteroid weaning may have a higher success rate as patients are selected on the basis of rejection history. Previous reports of HLA-DR mismatching and the long-term metabolic benefits with respect to corticosteroid weaning have been equivocal.

METHODS

One hundred and one eligible heart transplant recipients receiving triple-drug immunosuppression 6 months from heart transplantation were weaned from prednisone by decreasing the daily prednisone dose by 1 mg each month. Moderate rejection episodes were recorded and after conclusion of the study, HLA-DR mismatching of recipient and donor was reviewed. Serum cholesterol level, body weight, and number of patients receiving blood pressure medications were recorded before and 1 year after corticosteroid weaning.

RESULTS

Successful weaning from corticosteroids was achieved in 82% of patients. Of 31 patients with zero or one HLA-DR mismatch, 30 (97%) were successfully weaned. For those patients more than 1 year after discontinuation of corticosteroids, 67 had more weight loss and a lower serum cholesterol level than 15 patients who were unsuccessful at corticosteroid weaning and dependent on corticosteroids.

CONCLUSIONS

Heart transplant recipients can safely be weaned from corticosteroids late after heart transplantation with zero or one HLA-DR mismatch conferring a higher success rate. The long-term metabolic benefits of corticosteroid weaning include a reduction in weight and serum cholesterol.

Vascular cell adhesion molecule-1 is induced on vascular endothelia and medial smooth muscle cells in experimental cardiac allograft vasculopathy

BACKGROUND

Cardiac allograft vasculopathy (CAV) is the major cause of late death among heart transplant recipients. The pathogenesis of CAV is poorly understood.

METHODS AND RESULTS

To better characterize CAV, we performed immunohistochemical analysis of vascular lesions in a previously described murine model of CAV. The B10.A strain hearts were transplanted heterotopically into B10.BR strain recipients. The cardiac allografts were harvested from 1 to 2 months after implantation. The majority of epicardial and intramyocardial coronary arteries in explanted hearts had developed intimal thickening. The cellular infiltrate of the intimal thickening, major histocompatibility (MHC) antigens, intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) expression were studied with the use of immunohistochemistry. In experimental CAV in mice, the cellular infiltrate of expanded intima consisted of macrophages, T lymphocytes, and smooth muscle cells. A substantial number of macrophages and T lymphocytes within the expanded intima expressed MHC class II antigen, a marker of cellular activation. The vessel wall cells also appeared to be activated due to their expression of endothelium-leukocyte adhesion molecules. The vascular endothelium of cardiac allografts displayed ICAM-1, VCAM-1, and unmatched MHC antigen (MHC class I in this model) upregulation. The medial smooth muscle cells also expressed VCAM-1 and unmatched MHC antigen.

CONCLUSIONS

These findings suggest that (1) the cellular infiltrate of the expanded intima in experimental CAV is similar to that of human CAV, (2) experimental CAV is a local immune-mediated process requiring active participation of donor vessel wall cells and recipient mononuclear cells, and (3) coexpression of adhesion molecules and unmatched MHC antigen identifies endothelial cells as immune targets for activated host mononuclear cells. Furthermore, the presence of both VCAM-1 and unmatched MHC antigen supports a central role for medial smooth muscle cells as allogeneic immune stimulator.

Ventricular effluent of retrograde cardioplegia in human hearts has traversed capillary beds

BACKGROUND

In human hearts, as much as two thirds of retrograde cardioplegia is shunted through thebesian and arteriosinusoidal channels into the ventricular cavities. This ventricular effluent is believed to have bypassed the myocardial capillary beds and is therefore considered nonnutritive.

METHODS

To test this hypothesis, we studied the explanted hearts from 9 cardiac transplant recipients with the diagnosis of idiopathic cardiomyopathy. These hearts were arrested in situ with cold blood cardioplegia and excised with the coronary sinus intact. The left and right coronary ostia and the coronary sinus then were cannulated. Colored microspheres (15 +/- 5 microns) mixed in 37 degrees C blood cardioplegia were administered through the coronary sinus at a pressure of 30 to 40 mm Hg. Effluents from the coronary arteries and ventricular chambers were collected and analyzed for microsphere concentration.

RESULTS

Approximately 80% of retrograde cardioplegia solution was recovered in the ventricular chambers. Nearly 40% of this ventricular chambers effluent had traversed capillary beds and, thus, we believe has nutritive properties. Almost all of the coronary artery effluent of retrograde cardioplegia solution had traversed capillary beds. The total nutritive fraction of retrograde warm blood cardioplegia in this explanted human heart model was approximately 55%.

CONCLUSIONS

These findings suggest that the ventricular chamber effluent of retrograde blood cardioplegia contributes to the metabolic homeostasis of the arrested human heart.

Anomalous origin of the left main pulmonary artery from the ascending aorta associated with DiGeorge syndrome

We place on record 2 infants with the DiGeorge syndrome and anomalous origin of the left pulmonary artery from the ascending aorta. We postulate that: (1) embryogenesis of anomalous origin of the left pulmonary artery from the ascending aorta might be due to the persistent fifth aortic arch connecting both arterial systems; (2) an anomalous pulmonary artery arising from the ascending aorta is part of the aortic arch abnormality accompanied by normal conotruncal septation; and (3) in the DiGeorge syndrome, cardiac anomalies that originate from the conotruncus or aortic arch, or both, may have the same embryologic mechanisms.

The regional capillary distribution of retrograde blood cardioplegia in explanted human hearts

Warm retrograde blood cardioplegia is frequently used for myocardial protection, despite experimental studies questioning the adequacy of capillary flow to the right ventricle and septum. The capillary distribution of retrograde blood cardioplegia in the human heart is unknown. Hearts from eight transplant recipients with the diagnosis of idiopathic or dilated cardiomyopathy were arrested in situ with cold blood cardioplegia and excised with the coronary sinus intact. Within 20 minutes of explanation, colored microspheres mixed in 37 degrees C blood cardioplegia were administered through the coronary sinus at a pressure of 30 to 40 mm Hg for 2 minutes. Twelve transmural myocardial samples were taken horizontally at the level of midventricle and apex to determine regional capillary flow rates. When retrograde warm blood cardioplegia was administered at a rate of 0.42 +/- 0.06 ml/gm/min, the left ventricle, the septum, the posterior wall of the right ventricle, and the apex consistently received capillary flow rates in excess of their metabolic requirements. The capillary perfusion of anterior and lateral walls of the right ventricle was marginally adequate to sustain aerobic metabolism. In explanted human hearts, retrograde blood cardioplegia provides adequate capillary flow to the left ventricle, the septum, the posterior wall of the right ventricle, and the apex; however, capillary flow to the anterior and lateral walls of the right ventricle is marginal. This study delineates the tenuous balance between supply and demand for right ventricular protection with warm continuous retrograde blood cardioplegia.

Coronary sinus ostial occlusion during retrograde delivery of cardioplegic solution significantly improves cardioplegic distribution and efficacy

This study documents the gross flow characteristics and capillary distribution of cardioplegic solution delivered retrogradely with the coronary sinus open versus closed.

METHODS

Five explanted human hearts from transplant recipients were used as experimental models. Hearts served as their own controls and received two doses of warm blood cardioplegic solution, each containing colored microspheres. The first dose was delivered through a retroperfusion catheter with the coronary sinus open and the second dose was delivered with the sinus occluded. Capillary flow was measured at twelve ventricular sites and gross flow was measured by examining coronary sinus regurgitation, thebesian vein drainage, and aortic effluent (nutrient flow).

RESULTS

Coronary sinus ostial occlusion allowed for a significant decrease in total cardioplegic flow (1.74 +/- 0.40 ml/gm versus 1.06 +/- 0.32 ml/gm; p < 0.05) to occur while maintaining an identical intracoronary sinus pressure. Ostial occlusion also resulted in an increase in the ratio of nutrient flow/total cardioplegic flow from 32.3% +/- 15.1% to 61.3% +/- 7.9% (p < 0.05). A statistically significant improvement in capillary flow was found at the midventricular level in the posterior intraventricular septum and posterolateral right ventricular free wall. This improvement was also documented for the intraventricular septum and right ventricle at the level of the apex.

CONCLUSION

Coronary sinus occlusion during retrograde cardioplegia significantly improves cardioplegic delivery to the right ventricle and posterior intraventricular septum. Furthermore, the technique affords a significant improvement in nutrient cardioplegic flow while reducing the overall volume of cardioplegic solution administered.

Direct gene transfer into donor hearts at the time of harvest

Access to the donor heart at the time of harvest provides a unique opportunity for genetic manipulation of this organ before transplantation. We sought to determine (1) if donor mouse hearts express a foreign gene administered at harvest and, (2) if so, what route of gene delivery is most effective. At harvest, 30 micrograms of promoter cytomegalovirus-luciferase deoxyribonucleic plasmid in cationic liposomes was injected directly into the myocardial apex (group I), into the right atrium (group II), or into the coronary arteries (group III). The donor hearts were then transplanted into the abdomen of recipient mice of the same strain. The transplanted hearts were removed in 4 days and luciferase expression was assayed by immunohistochemistry. In group I, luciferase activity was localized to the apex. In group II, where plasmid was delivered into the right atrium, luciferase expression was detected in the right ventricle and sparsely in the coronary perivascular area. In group III, where plasmid was injected into the coronary arteries, the transplanted hearts demonstrated luciferase expression in (1) perivascular areas surrounding coronary arteries and veins, (2) coronary capillaries, and (3) the endocardia of both ventricles. This study suggests that (1) donor mouse hearts can be genetically modified at the time of harvest and (2) intracoronary infusion of plasmid yields the most effective method of delivery. Administration of plasmid in the coronary arteries localizes the expression to the endocardium and the coronary vasculature, both sites of immunologic interactions after heart transplantation.

The University of California at Los Angeles experience in heart transplantation

In the last decade, the number of patients undergoing heart transplantation has steadily increased as a result of expanding indications for cardiac transplantation. The limitation on the number of transplants performed has been the number of donor organs available. At UCLA, 511 heart transplant procedures were performed from 1984-1994. The mean number of rejection episodes and infections per patient in the first year after transplant was 1.1+/-1.3 and 1.0+/-1.2, respectively. Actuarial one-, 3-, and 5-year survival rates were 84%, 77% and 73%, respectively. Survival of patients age 60 years and over (n=105) was comparable to that of patients under age 60. Despite transplanting more critically ill patients (Status 1) and having longer cold ischemic times, outcomes have been improving. We have been pursuing corticosteroid-free immunosuppression, which no doubt has led to the decrease in infection complications. Furthermore, our work with pravastatin early after transplantation has led to a decrease in clinically severe rejection episodes which has translated into improved survival. Pravastatin also appeared to decrease the development of transplant coronary artery disease and appeared to have an adjunct immunosuppressive effect in our heart transplant patients on CsA-based immunosuppression. Future studies will include the use of mycophenolate mofetil which has properties against B-lymphocytes in addition to T-lymphocytes to block both humoral and cellular rejection. Our program continues to seek better ways to improve survival and the quality of life of our patient population.

Improvement in exercise capacity of candidates awaiting heart transplantation

OBJECTIVES

This study determined the frequency of improvement in peak oxygen uptake and its role in reevaluation of candidates awaiting heart transplantation.

BACKGROUND

Ambulatory candidates for transplantation usually wait > 6 months to undergo the procedure, and during this period symptoms may lessen, and peak oxygen uptake may improve. Whereas initial transplant candidacy is based increasingly on objective criteria, there are no established guidelines for reevaluation to determine who can leave the active waiting list.

METHODS

All ambulatory transplant candidates with initial peak oxygen uptake < 14 ml/kg per min were identified. Of 107 such patients listed, 68 survived without early deterioration or transplantation to undergo repeat exercise. A strategy of reevaluation using specific clinical criteria and exercise performance was tested to determine whether patients with improved oxygen uptake could safely be followed without transplantation.

RESULTS

In 38 of the 68 patients, peak oxygen uptake increased by > or = 2 ml/kg per min to a level > or = 12 ml/kg per min after 6 +/- 5 months, together with an increase in anaerobic threshold, peak oxygen pulse and exercise heart rate reserve and a decrease in heart rate at rest. Increased peak oxygen uptake was accompanied by stable clinical status without congestion in 31 of 38 patients, and these 31 were taken off the active waiting list. At 2 years, their actuarial survival rate was 100%, and the survival rate without relisting for transplantation was 85%.

CONCLUSION

Reevaluation of exercise capacity and clinical status allowed removal of 31 (29%) of 107 ambulatory transplant candidates from the waiting list with excellent early survival despite low peak oxygen uptake on initial testing. The ability to increase peak oxygen uptake, particularly with increased peak oxygen pulse, may indicate improved prognosis as well as functional capacity and, in combination with stable clinical status, may be an indication to defer transplantation in favor of more compromised candidates.