Acute rejection of the allogrfted human heart

Mechanical circulatory support systems: evolution, the systems and outlook

The joint efforts in the fields of surgery, medicine and biomedical engineering, sponsored by both the government and the industry, have led to the development of mechanical support devices that can provide reliable circulatory support, which can temporarily support a patient's circulation until either the heart recovers or until a new heart can be transplanted or permanently replace a failed heart. Their development has been driven by the shortage of donor organs. Various systems have eventually evolved for short or long-term support of patients suffering from cardiogenic and/or advanced heart failure (HF). Over time, several have been withdrawn from the market due to high rate of thromboembolism and pump-related complications, but many others remained with modern principles of circulatory support proved to be durable and reliable. Hopefully, the ever-evolving technology will yield several devices aimed at their miniaturization, with an energy supply without risk of infection, a system which is simple to implant and to exchange, minimalization of thrombus formation by optimal interior pump design, new antithrombotic medications and a system with demand-based pump activity. It is important to remember that such devices are only implanted to keep a patient alive or in an immediate life-threatening stage. In such circumstances, attribution of aforementioned difficulties to pump limitations or to advanced disease states remains difficult. In the coming years, ventricular assist devices (VADs) could be the most common surgical preference for treating severe HF.

Evolution of heart transplantation since Barnard's first

Barnard's first human heart transplantation in 1967 has paved the channel to numerous extensive researches and clinical experiences, mostly from the Stanford group, on orchestrating criteria for donor and recipient selection, immunosuppression, distant heart procurement, re-transplantation, and further global performance of the procedure until it became the gold standard therapy for end-stage heart failure, even in the face of an utterly limited organ availability. Much has happened since Barnard's first. There has been a rapid rise to 4,000-5,000 transplants per year. Previously, the number of transplants depended on the capacity of the units. Later on, it depended largely on the availability of donor organs. The widening of indications and reduction of contraindications to heart transplantations to include elderly patients >70 years, systemic diseases such as amyloidosis, has emerged. Indeed, heart transplantation has come a long way, and is considered a fruitful and stimulating episode in modern medicine. It is rather deplorable to watch that in the beginning of 1990s, the yearly number of heart transplantations began to decline-not because the operation had proved unsuccessful, but because donor hearts became scarce. It is rather poignant that although science and technology as well as increased experience accumulated over a long time have paved the way to make such an operation possible, its applicability is limited by lack of public awareness or its unwillingness to agree to organ donation. The average transplant survival is now over 10 years. Its prevalence and success, however, belies the fact that over 52 years ago, no one had ever attempted the procedure in man and that the procedure seemed destined for ignominy and failure just a year after the first transplant. Had it not been for the work of a few scientists and physicians, each who stepped on the broad shoulders of those who had come previously, the history of heart transplantation would be nothing more than a few legends and myths in dusty tomes.

Less Is More in Post Pediatric Heart Transplant Care

BACKGROUND

Historically, steroids and endomyocardial biopsies have, respectively, been part of standard immunosuppression for preventing cardiac transplant rejection and monitoring for rejection. However, these treatments come with numerous adverse effects. Some transplant programs have questioned whether the risks and costs outweigh the benefits or whether they may interfere with patient outcomes.

METHODS

Pediatric cardiac transplantations over 15 years (n = 49) were examined in a single-center retrospective study. Two groups of patients were formed: group 1 received induction steroids and underwent routine protocol biopsy (n = 18), and group 2 neither received steroids nor underwent routine biopsy (n = 13).

RESULTS

The 1-year survival rate was similar between the two approaches: group 1 survival was 94% and group 2 survival was 92%. However, differences between the two groups were observed for comorbidities. Group 1 had 11 patients that exhibited rejection, and group 2 had only 1 patient (p = 0.003). Group 2 had fewer cases of posttransplant hypertension (p = 0.001) and insulin dependence (p = 0.02).

CONCLUSIONS

This study suggests a less-invasive posttransplant approach that avoids biopsies and steroids was safely implemented in this single center. Both groups had similar survival. However, group 2 had statistically significant less posttransplant rejection, hypertension, and diabetes. Overall, this study shows no increased risk associated with steroid and biopsy avoidance in posttransplant patients, but with some clear benefits.

Cardiac Auscultation for Noncardiologists: Application in Cardiac Rehabilitation Programs: PART II: ADULT PATIENTS AFTER HEART SURGERY

This clinical skills review describes the most common cardiac auscultatory findings in adults after heart surgery and correlates them with prognostic indicators. It was written for noncardiologist health care providers who work in outpatient cardiac rehabilitation programs.Mechanical prosthetic valves produce typical closing and opening clicks. Listening to their timing and features, as well as to presence and quality of murmurs, contributes to the awareness of potential prosthesis malfunction before other dramatic clinical signs or symptoms become evident. In patients with biological prostheses, murmurs should be carefully evaluated to rule out both valve malfunction and degeneration. Rubs of post-pericardiotomy pericarditis should prompt further investigation for early signs of cardiac tamponade. Third and fourth heart sounds and systolic murmurs in anemic patients should be differentiated from pathological conditions. Relatively new groups of heart surgery patients are those with chronic heart failure treated with continuous-flow left ventricle assist devices. These devices produce characteristic continuous noise that may suddenly disappear or vary in quality and intensity with device malfunction. After heart transplantation, a carefully performed and regularly repeated cardiac auscultation may contribute to suspicion of impending acute rejection. During cardiac rehabilitation, periodic cardiac auscultation may provide useful information regarding clinical-hemodynamic status and allow detection of heralding signs of possible complications in an efficient and low-cost manner.

Advances in the understanding and management of heart transplantation

Cardiac transplantation represents one of the great triumphs in modern medicine and remains the cornerstone in the treatment of advanced heart failure. In this review, we contextualize pivotal developments in our understanding and management of cardiac transplant immunology, histopathology, rejection surveillance, drug development and surgery. We also discuss current limitations in their application and the impact of the left ventricular assist devices in bridging this gap.

Efficacy of signal-averaged electrocardiography in the young orthotopic heart transplant patient to detect allograft rejection

Endomyocardial biopsy is the gold standard survey for cardiac graft rejection. Signal-averaged electrocardiography (SAECG) identifies slowly conducting, diseased myocardium. We sought to determine whether SAECG is a sensitive, noninvasive transplant surveillance method in the young.Ninety-four SAECGs recorded prior to biopsy in 20 young transplant (OHT) patients and those from 15 healthy age-matched controls (CTL) were analyzed. In the OHT group, 56 no-rejection (NOREJ) (ISHLT grades 0 or 1 A) and 37 acute rejection (REJ) (ISHLT grades IB, 2, and 3A) SAECGs were compared, SAECGs were filtered at 40-255 Hz. Total QRS duration (QRSd), duration of terminal low amplitude of QRS under 40 microV (LAS), and root mean square amplitude of terminal 40 msec of QRS (RMS40) were compared.SAECGs were significantly different in CTL vs NOREJ but not in NOREJ vs REJ: QRSd, 81.7 +/- 8, 107.2 +/- 18.4, and 112.3 +/- 21.6 msec, respectively; LAS, (18 +/- 5.8, 23.6 +/- 10.7, and 27 +/- 14.8 msec, respectively; and RMS40, (169.3 +/- 100.4, 68 +/- 48.8, and 57.5 +/- 45.6 microV, respectively. Children following OHT exhibited significant differences in the SAECG compared to controls. Differences between the NOREJ and REJ groups were negligible. Therefore, SAECG may not be effective in detecting OHT rejection in the young.

Serial signal-averaged electrocardiography in children after cardiac transplantation

In patients with myocytolysis detected in endomyocardial biopsy, there is a tendency towards a shift of ventricular electrical axes from normal to strain pattern on surface ECG. Their 12-lead signal-averaged electrocardiogram (SAECG) show a significant increase in filtered QRS duration (QRSD) compared with those with specimens without myocytolysis. Late potentials were generally found more frequently in individual SAECG leads than in the vector magnitude. An increase in filtered QRSD and the presence of late potentials compared with a baseline study emphasizes the need for endomyocardial biopsy. Consequently, no change in these parameters may preclude the indication for endomyocardial biopsy.

Distribution and declines in cardiac allograft radionuclide left ventricular ejection fractions in relation to late mortality

BACKGROUND

Cardiac allograft left ventricular ejection fraction (LVEF) is an important measure of left ventricular systolic function. Despite widespread use of LVEF after transplantation, its normal range and prognostic value in cardiac allografts has not been defined.

METHODS

We conducted a retrospective cohort study among 292 consecutive adult heart transplant patients. Left ventricular ejection fractions were performed at 1, 3, 12, 24, and 48 months after transplantation using radionuclide ventriculography. Endomyocardial biopsies assessed rejection, right heart catheterization assessed loading conditions, and angiography assessed allograft coronary artery disease. We used Cox proportional hazards model to examine the predictive value of LVEF on late mortality.

RESULTS

Of the patients who survived > or =4 years, the mean allograft LVEF decreased 4.7 units at 3 months, from 63.8 to 59.7; an additional 4.1 units at 12 months, from 59.7 to 55.6 (p < 0.001); and remained stable afterward. These changes were not associated with concurrent changes in loading conditions, episodes of rejection, or development of allograft coronary artery disease. Left ventricular ejection fraction lower than the 95% normal limit (<40%) at 12 months was inversely associated with risk for late cardiac mortality (relative risk = 3.5, 95% confidence interval = 1.0-12.2), while controlling for recipient age, sex, donor age, and rejection episodes.

CONCLUSIONS

The cardiac-allograft LVEF frequently decreases in the first year after transplantation. The 95th percentile of allograft LVEF value (<40%) at Year 1 predicts late cardiac mortality among transplant recipients.

Are elevated levels of soluble ICAM-1 a marker of chronic graft disease in heart transplant recipients?

Positivity for circulating intercellular adhesion molecule-1 (ICAM-1) in heart transplant recipients has been claimed to predict the development of coronary artery disease and risk of graft failure. Soluble ICAM-1 were evaluated in 32 heart transplant recipients. Five of these patients, who had undergone transplantation several years before, were positive for soluble ICAM-1 but did not present any clinical sign of graft rejection. Furthermore, although heart graft coronary disease was diagnosed in 15 of the 32 patients, they did not show significantly higher titres of soluble ICAM-1 compared to the remaining patients. These findings suggest that major caution is necessary when considering ICAM-1 positivity as a marker of graft disease.

Severe and early alteration of action potential during acute cardiac rejection in rats

INTRODUCTION

Alteration of cardiac action potential and its adaptation to heart rate could contribute to cardiac dysfunction and arrhythmias during acute cardiac rejection.

METHODS AND RESULTS

Heterotopic heart transplantation was performed in allogeneic and syngeneic rats in which the action potentials of right and left ventricles were measured at 1, 2.5, 3.3, and 5.7 Hz successively using standard microelectrode techniques and compared with nontransplanted hearts. For each frequency, we measured action potential amplitude, action potential duration, transmembrane resting potential, and Vmax. In the right ventricle, at 1 Hz in the presence of rejection (n = 40), a significant increase was observed in action potential duration at 20%, 50%, and 70% repolarization (82.5%, 75.6%, and 70.8%, respectively) and in action potential amplitude (+17.9 mV), and the resting potential was decreased (-5.3 mV). A lack of adaptation of action potential duration to the driving frequency was observed in the rejecting heart group in contrast to controls (n = 20) and nonrejecting hearts (n = 13). Similar results were observed in the left ventricle and surprisingly in the native hearts (n = 11) of recipients with allografted rejecting hearts in the abdominal position.

CONCLUSION

Action potential and its adaptation to the driving frequency is considerably altered during acute rejection. A humoral factor could contribute to cardiac dysfunction.

The role of echocardiography in heart transplantation

Echocardiography has gained increasing importance as an imaging modality in the care of the cardiac transplant recipient. Its utility in detecting the complications of transplantation, with special reference to the diagnosis of rejection and graft arteriosclerosis, is discussed. On the basis of a review of the current literature, an outline for serial echocardiographic studies is proposed.

Current usefulness of the signal-averaged electrocardiogram

Signal-averaged electrocardiography is a relatively simple, noninvasive technique by which valuable information can be gained to help in the management of patients with cardiovascular disease. The presence of late potentials on the SAECG is a good marker for the presence of an arrhythmogenic substrate that is believed to be the source of ventricular tachycardia in patients with coronary artery disease. The value of the detection of late potentials has been studied best after myocardial infarction, when the absence of late potentials makes the occurrence of an arrhythmic event very unlikely. The positive predictive value for an arrhythmic event to occur in the presence of late potentials is low, however, comparable to the predictive value of decreased left ventricular function, complex ventricular ectopy, or abnormal autonomic tone. This appears to have its explanation in the complex pathophysiology behind the occurrence of arrhythmic events. Improved accuracy for the SAECG is achieved when the result of the test is interpreted with consideration of the presence or absence of other predictive markers. A thorough understanding of the signal-averaged electrocardiogram makes optimal clinical use of the information gained from this easily acquired test possible.

Signal-averaged electrocardiography and detection of heart transplant rejection: comparison of time and frequency domain analyses

To evaluate the role of the signal-averaged electrocardiogram (ECG) in the detection of heart transplant rejection, findings on 277 ECGs were compared with those in 218 endomyocardial biopsy specimens in 25 patients followed up for a median duration of 5.2 months (range 7 days to 17.5 months). Signal-averaged ECGs obtained at intervals of 16.4 +/- 22.3 days were analyzed in the time domain before and after high pass filtering at 25 and 70 Hz. Frequency domain analysis was performed with use of a fast Fourier transform algorithm. Sixteen severe rejection episodes requiring treatment were observed. These episodes induced significant decreases in peak and root-mean-square voltages of both filtered and unfiltered QRS complexes, as well as in the total spectral area. Conversely, QRS duration and 50- to 250-Hz or 70- to 110-Hz spectral areas were not significantly altered. In 14 cases mild rejection episodes were observed that did not significantly alter any of the variables studied. The root-mean-square voltage of the 70-Hz high pass filtered QRS complex was found to be the most accurate variable in detecting rejection. Moreover, this variable was also the most reproducible in 10 healthy control subjects. The optimal rejection criterion was defined as an 11% decrease in voltage between two consecutive recordings. It provided 87.5% sensitivity with 78.4% specificity. In conclusion, the signal-averaged ECG is helpful in the management of heart transplant rejection. Frequency domain analysis of the QRS complex does not increase the accuracy of the technique compared with the time domain approach.

Alterations in left ventricular diastolic twist mechanics during acute human cardiac allograft rejection

BACKGROUND

Contraction of obliquely oriented left ventricular (LV) fibers results in a twisting motion of the left ventricle. The purpose of this study was to assess the effects of acute human cardiac allograft rejection on LV twist pattern and the twist-volume relation.

METHODS AND RESULTS

Tantalum markers were implanted into the LV midwall in 15 transplant recipients to measure time-varying, three-dimensional chamber twist using computer-assisted analysis of biplane cinefluoroscopic images. Twist was defined as the mean longitudinal gradient of circumferential rotation about the LV long axis. When plotted against normalized percent ejection fraction (%EF), the resulting twist-normalized %EF relation could be divided into three phases. In systole, LV twist was linearly related to ejection of blood. In contrast, diastolic untwist was characterized by early rapid recoil with little change in LV volume, followed by more gradual untwisting when the bulk of diastolic filling occurred. During 10 acute rejection episodes in 10 patients, maximum twist, peak systolic twist rate, and the slope of the systolic twist-normalized %EF relation did not change. In contrast, the slope of the early (first 15% of filling) diastolic twist-normalized %EF relation (M(early-dia)) decreased significantly (-0.194 +/- 0.062 [prerejection] versus -0.103 +/- 0.054 rad/cm [rejection], p = 0.0003), resulting in a prolonged tau 1/2 (time required to untwist by 50% [20 +/- 5% versus 28 +/- 5% of diastole], p = 0.0003) and decrease in percent untwisting at 15% diastolic LV filling (62 +/- 11% versus 36 +/- 13%, p = 0.0003). Therefore, a greater proportion of LV untwisting occurred later in diastole during rejection, as reflected by an increase in the slope (M(mid-dia)) of the middle to late (from 15 to 90% filling) diastolic twist-normalized %EF relation (-0.018 +/- 0.009 versus -0.030 +/- 0.010 rad/cm, p = 0.0015). Peak rate of untwist was not affected. With resolution of rejection, M(early-dia) and percent untwist during early diastole returned to baseline levels (p = NS versus baseline). There was also a trend for M(mid-dia) to return toward prerejection values (p = NS versus baseline), but this change did not reach statistical significance compared with rejection values.

CONCLUSION

Acute cardiac allograft rejection is associated with altered diastolic twist mechanics in the absence of any demonstratable systolic abnormalities. During rejection, myocardial edema and other factors may result in intrinsic changes of the elastic properties of the myocardium, thereby leading to modification of recoil forces responsible for the early, rapid unwinding of the deformed ventricle.

Differentiation of constrictive pericarditis and restrictive cardiomyopathy by Doppler echocardiography

Doppler ultrasound recordings of mitral, tricuspid, aortic, and pulmonary flow velocities, and their variation with respiration, were recorded in 12 patients with a restrictive cardiomyopathy and seven patients with constrictive pericarditis. Twenty healthy adults served as controls. The patients with constrictive pericarditis showed marked changes in left ventricular isovolumic relaxation time and in early mitral and tricuspid flow velocities at the onset of inspiration and expiration. These changes disappeared after pericardiectomy and were not seen in patients with restrictive cardiomyopathy or in normal subjects. The deceleration time of early mitral and tricuspid flow velocity was shorter than normal in both groups, indicating an early cessation of ventricular filling, but only patients with restrictive cardiomyopathy showed a further shortening of the tricuspid deceleration time with inspiration. Diastolic mitral and tricuspid regurgitation was also more common in the patients with restrictive cardiomyopathy. These results suggest that patients with constrictive pericarditis and restrictive cardiomyopathy can be differentiated by comparing respiratory changes in transvalvular flow velocities. In addition, although baseline hemodynamics in the two groups were similar, characteristic changes were seen with respiration that suggest differentiation of these disease states may also be possible from hemodynamic data.

A hemodynamic and Doppler echocardiographic study of ventricular function in long-term cardiac allograft recipients. Etiology and prognosis of restrictive-constrictive physiology

Conventional hemodynamic measurements and Doppler echocardiography were used to assess ventricular physiology of the human cardiac allograft and to examine the influence of pertinent clinical factors on chronic myocardial performance. Sixty-four patients (18-55 years old; mean, 39 years) undergoing routine annual hemodynamic assessment were studied. Blood-flow velocity properties across the mitral, tricuspid, and aortic valves were analyzed from Doppler ultrasound recordings. Ten of these patients had elevated diastolic pressures associated with a sharp early diastolic dip followed by an exaggerated and abrupt rise in pressure, consistent with restrictive-constrictive ventricular physiology. Left ventricular dP/dt and stroke volume were lower in these patients compared with the other 54 patients. Doppler echocardiographic indexes of left ventricular filling and ejection in these 10 patients differed significantly. Isovolumic relaxation time and pressure half-time were shorter, peak early mitral and tricuspid flow velocities were higher, and mean aortic flow velocity and acceleration were lower. A higher rejection incidence was the only demonstrable clinical factor associated with impaired ventricular function. Doppler echocardiography may, therefore, noninvasively identify patients with hemodynamic evidence of restrictive-constrictive physiology. This abnormality occurs in approximately 15% of allograft recipients, is associated with impaired systolic performance, and may be related to rejection incidence.

Acute rejection after cardiac transplantation: detection by interstitial myocardial pH

Intramyocardial pH was assessed as a potential marker for clinical evaluation and treatment of acute rejection following cardiac transplantation. Fifteen cats underwent forty operative procedures. Following intra-abdominal heterotopic heart transplantation, serial laparotomies were performed in the early (days 0 to 2), intermediate (days 5 to 7), and late (days 7 to 16) postoperative periods. Rejection was assessed by serial clinical examinations, ECG analyses, B-mode echocardiography, histological and ultrastructural analyses, and measurements of interstitial myocardial pH. Intramyocardial pH was measured by a new miniature (0.6 X 3.0 mm) fiberoptic pH transducer. At confirmed rejection, concomitant laparotomy and thoracotomy were performed and pH sensors were implanted in both native (anatomical) and graft hearts. Nine animals at rejection were given methylprednisolone and changes in graft and native heart pH were measured. The pH during absence of rejection, mild acute rejection, and severe acute rejection averaged 7.430 +/- 0.019, 7.233 +/- 0.040 (p less than .02), and 6.860 +/- 0.066 (p less than .02), respectively (mean +/- standard error of the mean). A progressive decline in pH was noted in each heart. In animals receiving steroids, graft heart pH increased over 90 minutes from 6.852 +/- 0.065 to 7.043 +/- 0.077 (p less than .05). Although pH decline may be secondary to either inflammatory or ischemic etiology, histological and ultrastructural analyses demonstrate a predominant inflammatory response with progressive mononuclear cell infiltration, interstitial edema, vascular wall edema, infiltration by polymorphonuclear neutrophil leukocytes, vacuolation of sarcoplasmic reticulum, and disarray of myocytes associated with falling pH. Degree of pH change correlated closely with degree of histological rejection, presence of ECG voltage decline, and change in wall thickness by ultrasound.

Human cardiac transplantation--evaluation of morphological changes in serial endomyocardial biopsies

From May 1981 through July 1984 a total of 29 human allogenic orthotopic cardiac transplants were performed in Munich. The first two patients initially received conventional immunosuppressive treatment for 79 and 27 days, respectively; then treatment was continued with cyclosporine. All subsequent 27 patients received only cyclosporine treatment. Seventeen of the cardiac recipients are currently alive. Three of the recipients who died succumbed to immunological rejection. Twenty-five cardiac grafts were controlled by 355 sequential biopsy procedures, which yielded 1158 endomyocardial specimens for histological examination. The morphological findings and changes observed in the endomyocardium were analyzed. The interpretation of these findings and difficulties encountered in their interpretation are discussed. Special attention is attributed to findings possibly associated with the cyclosporine treatment.

Prosepctive analysis of heart biopsies in coronary artery surgery

In a prospective analysis of 36 biopsies from human hearts performed at the time of elective coronary operation, several morphological changes were identified in the myocardium. Some of these changes (fibrosis, vacuolation, edema, and amyloid deposition) are of clinical signficance and may affect the long-term prognosis for patients undergoing revascularization procedures. It appears, therefore, that knowledge of the morphological state of the myocardium at the time of operation can prove useful in elucidating further the long-term effects of coronary artery bypass on the left ventricular myocardium.

Improved immunosuppression for cardiac transplantation: immune monitoring and individualized modulation of recipient immunity by in vitro testing

These studies demonstrate that immune monitoring and individualized modulation of recipient immune reactivity using a quality-controlled preparation of rabbit antithymocyte globulin can improve results of cardiac transplantation. The most valuable assay in individualizing drug doses was the serial measurement of T-cell levels using a complete lymphocyte profile technique and monitoring with phytohemagglutinin to rule out false low T-cell levels. Using this system, the incidence and severity of early rejections were markedly reduced and no grafts were lost to rejection in the first month. The recent first-year graft survival has been about 60%, an improvement largely related to a reduction in early rejection and infection. This technique of immunosuppression appears quite promising for improving the results of future cardiac transplantations.

Human heart transplantation: current status

The overall survival rate for 97 heart transplant recipients operated on from 1968 to 1975 has been 49% at one year and 23% at five years. Progressive improvement in one-year survival has been achieved, from 22% in 1968 to 62% in 1974. The major factors responsible for increasing survival are better understanding and management of acute and chronic rejection. Current results suggest that heart transplantation deserves wider application in the treatment of selected patients with end-stage myocardial insufficiency.

Alterations in T and B lymphocytes in heart transplant patients early and late postoperatively

Alterations in the percent and absolute number of thymus-derived (T) and bursa-equivalent (B) lymphocytes in peripheral blood were followed in 10 patients treated with antithymocyte globulin, prednisone, and azathioprine after cardiac transplantation. During the 1st postoperative wk the percent of T cells dropped below 10% in almost all cases (normal range, 65-91%) with a concomitant rise in the percent of B cells. However, the absolute T- and B-cell counts were both markedly depressed (less than 200 cells/mm3). During the 7-wk postoperative period the percent of T cells rose to 45-60% and the absolute count rose from 100 to 350 cells/mm3 (normal range, 1,092-2,400 cells/mm3). Although the percent of B cells was elevated (35-50%) during this period, the absolute B-cell count remained below the range of normals (268-640 cells/mm3). Follow-up of long-term survivors (3-60 mo postoperative) showed a continued marked T (467 cells/mm3) and B (95 cells/mm3) lymphocytopenia. Chronological relationships between the percent and absolute T-cell count and episodes of graft rejection in individual patients are discussed as possible adjuncts in the prediction of rejection crises.

Arrhythmias in two patients with left ventricular bypass transplants

Two patients who underwent left ventricular bypass transplants are described. Both patients sustained postoperative rhythm disturbances of their own hearts during sinus rhythm of the donor hearts. Illustrative examples of atrial flutter, ventricular flutter, ventricular fibrillation, blocked atrial extrasystoles, and double ventricular parasystole in the recipient hearts are presented. The patients tolerated all these arrhythmias well during uninterrupted sinus rhythm in the donor heart. The problems in interpretation of arrhythmias in the presence of two hearts are discussed.

Coronary arteriography in long-term human cardiac transplantation survivors

Coronary arterial lesions in survivors of cardiac transplantation result from accelerated coronary atherosclerosis. Clinical recognition of this event is difficult but essential for long-term management and prognostication. Coronary arteriography was performed on 30 occasions in a group of 16 patients 1-4 years after cardiac transplantation. Fifteen patients had normal coronary arteries at one year. Of 10 patients studied at two years, seven showed no change but three others revealed significant coronary arterial lesions which correlated well with clinical signs of coronary artery disease. These three patients subsequently died, two due to coronary artery disease, one due to infection. Three patients have remained normal at three years and one patient is normal at four years as evidenced on yearly coronary arteriograms. A postmortem examination of the patients who died with coronary artery disease confirmed the extent of the luminal narrowing due to atheromatous plaques superimposed on intimal lesions. Coronary arteriography has proven to be a safe, reliable method for assessing the coronary circulation of long-term cardiac transplant survivors.

Lymphocyte tissue culture studies on human heart transplant recipients. I. Screening recipients for serum factors which inhibit the mixed lymphocyte reaction

The sera of 20 random human heart transplant recipients, drawn before the administration of immunosuppressive medications, were screened for the presence of factors that might inhibit the mixed lymphocyte reaction. The donors for the lymphocyte cultures were unrelated both to one another and to the heart donor and recipient. Inhibition was defined as a reduction of the number of transformed cells produced in vitro to less than one-third of that produced in autologous serum. It appears that patients who have had previous heart surgery on bypass fare better with heart transplants than those who have not had surgery. This may indicate some change in the overall physiology of the former class of patients resulting in better acceptance of the transplant. In turn, this could be due to the development of a serum factor or an impairment in the patients' cellular immune systems. In the series of recipients studied, the majority possessed serum inhibitory factors possibly non-specific by-products of their heart failure. The precise nature of these factors has yet to be determined. Future research is planned to determine whether bypass surgery is responsible for the stimulation of new immuno-depressive factors or if in some way it boosts the titer of pre-existing factors.

Acute rejection in the long-term cardiac transplant survivor. Clinical diagnosis, treatment and significance

Thirty-two of 59 patients undergoing cardiac transplantation at Stanford University Medical Center since January, 1968, have survived longer than three months. In 19 of these long-term survivors 47 episodes of late acute rejection occurred. In the first two months post-transplantation the incidence of acute rejection is one episode per 20.5 patient days, but between four and 12 months post-transplantation decreases to one episode per 200 patient days. Late acute rejection episodes are usually clinically mild and can be detected by electrocardiographic changes, evidence of mild graft dysfunction and characteristic histologic changes in tissue obtained by transvenous endomyocardial biopsy. Out-patient treatment with increased oral prednisone has successfully reversed 70% of these late acute rejection episodes, with the other 30% requiring more aggressive therapy. Late acute rejection or complications related to its treatment have contributed to the death of three long-term survivors and has been implicated as a causative factor in the development of graft coronary atherosclerosis in six patients in the earlier part of our series. However, the occurrence of acute rejection in the long-term cardiac transplant patient does not preclude good graft function and patient survival in the majority of patients.