Candidate Selection for Heart Transplantation

Benefits of a Supervised Ambulatory Outpatient Program in a Cardiovascular Rehabilitation Unit Prior to a Heart Transplant: A Case Study

Preoperative peak oxygen uptake (V.O2peak) and ventilatory efficiency (V.E/V.CO2slope) are related to the vital prognosis after cardiac transplantation (HTx). The objective of our study was to evaluate the effects of exercise-based cardiac rehabilitation (ECR) program on the preoperative exercise capacity of a HTx candidate. A male patient, aged 50–55 years, with chronic heart failure was placed on the HTx list and performed 12 weeks of intensive ECR (5 sessions-a-week). Our results showed that the cardiac index continuously increased between the onset and the end of ECR (1.40 vs. 2.53 L.min–1.m2). The first 20 sessions of ECR induced a V.O2peak increase (15.0 vs. 19.3 ml.min–1.kg–1, corresponding to 42.0 and 53.0% of its maximal predicted values, respectively). The peak V.O2 plateaued between the 20th and the 40th ECR session (19.3 vs. 19.4 ml.min–1.kg–1) then progressively increased until the 60th ECR session to reach 25.7 ml.min–1.kg–1, i.e., 71.0% of the maximal predicted values. The slope of V.E/V.CO2 showed a biphasic response during the ECR program, with an increase between the onset and the 20th ECR session (58.02 vs. 70.48) and a decrease between the 20th and the 40th ECR session (70.48 vs. 40.94) to reach its minimal value at the 60th ECR session (31.97). After the first 40 sessions of the ECR program, the Seattle Heart Failure Model score predicted median survival time was estimated at 7.2 years. In conclusion, the improvement in exercise capacity and cardiorespiratory function following the ECR helped delay the heart transplant surgery in our patient awaiting heart transplantation.

Psychosocial and behavioral selection criteria for solid organ transplantation

An evidence-based selection process for organ transplantation may be a valuable approach to improve posttransplant outcomes. This paper reviews state-of-the-art psychosocial and behavioral selection criteria and assesses their validity in view of predicting outcomes after transplantation. Psychosocial factors addressed are psychiatric disorders, mental retardation, irreversible cognitive dysfunction, and lack of social support. Behavioral selection criteria discussed are alcoholism, smoking, drug abuse, and obesity. This review reveals that the evidence concerning these selection criteria in scarce. There is a definite need for more longitudinal research to strengthen the scientific basis of the psychosocial and behavioral dimension of transplantation.

Evaluation of the potential role of color-coded tissue Doppler echocardiography in the detection of allograft rejection in heart transplant recipients

BACKGROUND

Color-coded tissue Doppler (TD) echocardiography can noninvasively quantify alterations in left ventricular (LV) systolic and diastolic function. The objective of this study was to test the hypothesis that TD may play a role in the detection of LV dysfunction associated with allograft rejection in heart transplant recipients.

METHODS AND RESULTS

Seventy-eight consecutive transplant recipients underwent 89 TD studies of posterior wall myocardial velocity gradient and mitral annular velocity within 1 hour of endomyocardial biopsy. Color TD echocardiographic images were digitized for semiautomated computer analysis. Histologic analysis revealed no significant rejection in 75 biopsies and significant rejection in 14. TD posterior wall peak systolic and diastolic velocity gradients were reduced significantly with rejection: 3.9 +/- 2.0 s(-1) versus 2.6 +/- 0.9 s(-1) and 5.4 +/- 2. 4 s(-1) versus 3.5 +/- 1.6 s(-1), respectively (P <.05 vs the nonrejecting group). Peak systolic and diastolic mitral annular velocities by TD were also reduced with rejection: 63 +/- 14 mm/s versus 49 +/- 12.4 mm/s and 90 +/- 23 mm/s versus 60 +/- 21 mm/s, respectively (P <.001 vs the nonrejecting group). A TD peak-to-peak mitral annular velocity >135 mm/s had 93% sensitivity, 71% specificity, and 98% negative predictive value for detecting rejection. Although TD was unable to discriminate between rejection and other causes of low velocity values, high TD velocity values were supportive of excluding rejection.

CONCLUSIONS

These data suggest that color-coded TD may play a potential role as a screening test to exclude rejection in heart transplant recipients. Although this method has the potential to decrease the number of biopsies, further testing in a larger series of transplant recipients with rejection is warranted.

Managing inotrope therapy noninvasively

Intermittent and continuous outpatient and home inotrope infusions have contributed to a decreased mortality rate and improved quality of life in the patient with end-stage congestive heat failure. Before the advent of noninvasive hemodynamic monitoring, available with thoracic electrical bioimpedance, initial dosage and titration were determined solely with invasively acquired data requiring hospital admission or with patients' subjective data. Thoracic electrical bioimpedance monitoring of patients receiving inotrope therapy provides objective documentation of drug efficacy, developing tolerance, and optimal dosage.

Beneficial effects of intermittent home administration of the inotrope/vasodilator milrinone in patients with end-stage congestive heart failure: a preliminary study

BACKGROUND

End-stage congestive heart failure (CHF) is associated with a high mortality rate and is often refractory to standard medical treatment. Although parenteral inotropes have been beneficial in hospitalized patients, their use in outpatients has been limited by toxicity and tachyphylaxis.

METHODS AND RESULTS

To determine whether patients with end-stage CHF could safely tolerate intermittent outpatient inotropic therapy and demonstrate both symptomatic and functional improvement with these agents, we studied the effects of low-dose, intermittent home infusions of the inotrope/vasodilator milrinone in 10 patients with end-stage CHF. After showing hemodynamic improvement with milrinone while hospitalized, central lines were placed and patients were given the drug at home with small portable infusion pumps, starting at 3 days a week for 6 hours at a time over a 3-month period. Patients tolerated the drug well, with no deaths and a fourfold decrease in hospitalizations during the study. Arrhythmias were minimal and angina decreased in two patients. Mean total, physical, and emotional scores on the Minnesota Living with Heart Failure Questionnaire reflected a general trend of symptomatic improvement throughout the infusion period. The mean number of reported hours of improvement after infusion progressively increased throughout the study, producing a mean of 25 hours of postinfusion improvement during the final week (p < 0.01). Repeat hemodynamic study at the end of the 3-month period showed trends toward improvement in cardiac function.

CONCLUSIONS

This is the first study to demonstrate safety, efficacy, hemodynamic, and functional improvement in patients receiving low-dose, intermittent outpatient milrinone therapy. We believe this improvement partly relates to a "training" effect on the heart or peripheral muscles and circulation. These promising results suggest that given appropriately, inotropes have an important therapeutic role in the outpatient treatment of end-stage CHF.

Experimental cardiomyopathy as a model of chronic heart failure

End-stage heart disease is a major health care issue and it represents one of the most costly diseases. Several experimental heart failure models have been developed; however, a single model is not widely accepted as representative of clinical heart failure. The doxorubicin-induced cardiomyopathy model was used in the current study to address two issues: 1) to define a standardized dose regimen of intracoronary doxorubicin infusion; and 2) to establish a method of determining the onset and time course of heart failure. Twenty dogs underwent placement of an intracoronary catheter. A total dose of 1 mg/kg of intracoronary doxorubicin was infused. Hemodynamics were obtained at weeks 0, 7, and 12. Echocardiography was performed weekly. Right and left ventricular biopsy specimens were examined at weeks 0 and 12. Survival after doxorubicin-induced cardiomyopathy was 60% at week 12. The development of heart failure was demonstrated by a significant decrease in left ventricular ejection fraction and cardiac index and a significant increase in left ventricular end-diastolic pressure and volume. The leukocyte count, hemoglobin, and hematocrit decreased significantly. Histologic changes of both the right and left ventricular myocardial biopsy specimens included myocellular hypertrophy, loss of myofibrillar material, and vacuolization. Intracoronary doxorubicin reliably produced an experimental model of accelerated heart failure that developed over the course of 12 weeks. Echocardiographic monitoring allowed a close surveillance of heart failure development. This model may be useful to evaluate the efficacy of cardiomyoplasty, mechanical assist devices, transplantation, and reduction ventriculoplasty.

Exercise-related ventilatory abnormalities and survival in congestive heart failure

This retrospective study of 104 New York Heart Association class 1 to 4 heart failure patients undergoing exercise stress testing with gas exchange analysis demonstrated that the ventilatory equivalent for carbon dioxide at anaerobic threshold is useful in determining prognosis in patients with severe congestive heart failure, particularly when used in combination with peak exercise oxygen consumption. A ventilatory equivalent for carbon dioxide >50 and peak oxygen consumption < or =15.0 ml/kg/min defines a very high-risk patient group who should be prioritized for transplantation.