Trends in patient selection for heart transplantation

Does oxygen saturation or distance walked predict rehospitalization in heart failure?

BACKGROUND

Hospitalized heart failure (HF) patients experience high rehospitalization rates. Predicting early rehospitalization risk in HF patients may enable better decision making at time of hospital discharge. It is known that sex and ethnicity influence rehospitalization rates. Several measures easily and conveniently obtained before discharge are arterial oxygen saturation (SaO2) and distance walked during the 6-minute walk test (6MWT).

RESEARCH OBJECTIVE

The aim of this pilot study was to examine sociodemographic (sex and ethnicity) and clinical (oxygenation and distance walked) variables obtained during a predischarge 6MWT that could indicate increased risk of cardiac rehospitalization within 90 days.

METHODS

Within 24 hours of discharge, 44 hospitalized HF patients underwent 6MWT with continuous SaO2 and heart rate monitoring. Demographic data, past medical history, and medication use were collected from the patients' charts.

RESULTS

Participants' mean (SD) age was 59.6 (18.6) years, with half (n = 22) being Caucasian/white and one-quarter (n = 11) being married. Half (n = 22) were anemic on admission. Mean (SD) SaO2 was 94.2% (3.6%), mean (SD) minimum SaO2 was 89.1% (6.1%), and mean (SD) 6MWT was 220.8 (111.6) m. More than half (n = 23) were rehospitalized for cardiac reasons. Women had a 2.5 times greater risk of rehospitalization than men did. Women were significantly more anemic and walked shorter distances. There was no relation between distance walked or SaO2 and rehospitalization risk.

CONCLUSION

Although there was no relation between SaO2 and rehospitalization risk, women had a greater risk of rehospitalization, were more frail, and were more often anemic. This study is novel because it establishes a link between sex, anemia, functional status, and rehospitalization risk in patients hospitalized for HF. More research is needed to better understand the influence of anemia, functional status, and sex in relation to rehospitalization risk.

Heart failure in women

Heart failure affects more than 5 million Americans. Each year, about 400,000 individuals develop heart failure, making it the nation's most rapidly growing cardiac problem. Almost one third of these individuals have New York Heart Association Functional Class III or IV heart failure and are faced with progressive clinical deterioration and frequent hospital admissions. These figures will continue to escalate as the population ages. The success of interventional procedures and pharmacologic therapies in the management of coronary artery disease has enabled this population to survive acute events, at the same time creating a population with chronic disease. Common etiologies of heart failure in women include coronary artery disease, myocardial infarction, and valvular disease. However, women are at especially high risk for developing heart failure due to diastolic dysfunction associated with hypertension and diabetes. Heart failure in women is best managed across the care continuum, incorporating pharmacologic agents, interventional procedures when appropriate, dietary restrictions, self-monitoring, and psychosocial support. Much of the recent literature has focused on women and heart disease. This emphasis is partly due to public misconception about women's health problems and the growing body of research distinguishing gender differences. Significant advances in therapy have been made to improve the quality and span of life for people with heart disease. Despite therapeutic advances, however, women have high mortality rates from heart disease, including heart failure due to ischemic causes. In fact, women with heart failure present differently than men and have different etiologies and treatment options. As we learn more about women and heart disease, the distinguishing differences unfold and become helpful in establishing a plan of care.

Rationale for the short term use of intravenous milrinone under hemodynamic guidance in patients with severe systolic heart failure

Patients with severe systolic heart failure have a decrease in both number and function of cardiac beta receptors, which may result in a poor inotropic response to I.V. beta-adrenergic agonists such as dobutamine. The I.V. use of the phosphodiesterase inhibitor milrinone, which is a combined positive inotrope/vasodilator in this patient population, is a more rational choice, especially if heart failure is chronic. Many of these patients may also be referred for consideration for cardiac transplantation, for which the use of invasive hemodynamic monitoring is typically necessary to determine whether severe hemodynamic compromise and pulmonary hypertension are reversible with therapy. The use of hemodynamically guided I.V. vasodilator therapy has also been extensively described as a tool to optimize oral vasodilator therapy and predict prognosis in patients evaluated for cardiac transplantation. This review summarizes the important studies supporting the rationale for and benefits of using I.V. milrinone under hemodynamic guidance in this patient population. (c)2000 by CHF, Inc.

[Prevention of sudden death in patients awaiting heart transplantation]

Sudden death, unexpectedly alters outcome in many patients awaiting heart transplantation. The prevention of sudden death in these patients has been the focus of intensive research to achieve a larger number of patients who finally receive transplants. Recent advances in the medical treatment of heart failure, have reduced mortality and in particular, that caused by sudden death. Nonetheless sudden death remains a frequent cause of mortality in patients awaiting cardiac transplantation. The recognition of patients at very high risk for sudden death is relatively easy, but most patients who suffer sudden death while awaiting cardiac transplantation, are not among those initially included in the overall high risk category. The betablockers, when patients are able to use them, can reduce sudden and total mortality. Class I antiarrhythmic drugs should not be used in patients with cardiac failure. Amiodarone does not increase mortality and may have a beneficial effect in some patients, but its efficacy is lower than that of the implantable defibrillator and its widespread use is not justified. The implantable defibrilator is the reference treatment to reduce sudden death in selected patients, awaiting transplantation.

The implantable cardioverter defibrillator as a "bridge to transplant": a viable clinical strategy?

Heart transplantation is an accepted therapeutic option for patients with end-stage heart disease. However, because the availability of heart donors fails to keep pace with the growing demand, increasing numbers of potential recipients are placed on the waiting list, resulting in longer waiting times. About 20% of patients die while awaiting heart transplantation. The majority die from progressive pump failure (46%), whereas about 30% of all deaths occur suddenly. Monitored terminal cardiac electrical activity in patients dying while awaiting transplantation reveals that bradyarrhythmias and/or electromechanical dissociation are involved in 68% of cases and ventricular tachyarrhythmias in 32% of cases. Patients with a history of aborted cardiac arrest are at highest risk for recurrent malignant arrhythmias. The implantable cardioverter defibrillator (ICD) is the most effective therapy for preventing sudden cardiac death from ventricular tachyarrhythmias. Pooled data from a total of 75 sudden death survivors listed for cardiac transplantation demonstrate that ICD therapy can be applied with low mortality, low morbidity, and high efficacy, with up to 94% of the patients receiving appropriate shocks during the waiting period. However, there is considerable concern that this early survival benefit conferred by the ICD may be nullified by the competing risk of death due to terminal pump failure, as the waiting list and waiting time to transplantation lengthens. In advanced heart failure, risk stratification for sudden tachyarrhythmic death is only of limited value. Therefore, although sudden tachyarrhythmic death appears to constitute only a minor fraction of total cardiac death in patients awaiting heart transplantation, prophylactic ICD implantation as on electronic bridge to transplant may be considered. To define conclusively the role of prophylactic ICD therapy in this setting, prospective randomized studies are needed.

Impact of a comprehensive heart failure management program on hospital readmission and functional status of patients with advanced heart failure

OBJECTIVES

To assess the impact of a comprehensive heart failure management program, functional status, hospital readmission rate and estimated hospital costs were determined and compared for the 6 months before and the 6 months after referral.

BACKGROUND

The course of advanced heart failure is characterized by progressive clinical deterioration reflected in frequent hospital admissions, which comprise the major financial cost.

METHODS

Over a 3-year period, 214 patients were accepted for heart transplantation and discharged after evaluation, which included adjustments in medical therapy and intensive patient education. Patients were in New York Heart Association functional class III or IV (94 and 120 patients, respectively), with a mean left ventricular ejection fraction of 0.21, peak oxygen consumption of 11 ml/kg per min and a total of 429 hospital admissions in the previous 6 months (average 2.0 per patient). Changes in the medical regimen included a 98% increase in angiotensin-converting enzyme inhibitor dose and a flexible diuretic regimen after 4.2-liter net diuresis, with counseling also regarding diet and progressive exercise.

RESULTS

During the 6 months after referral, there were only 63 hospital readmissions (85% reduction), with 0.29/patient (p < 0.0001). Functional status improved as assessed by functional class (p < 0.0001) and peak oxygen consumption (15.2 vs. 11.0 ml/kg per min, p < 0.001). The same results were seen after excluding the 35 patients without full 6-month follow-up (9 deaths, 14 urgent transplant procedures during hospital readmission, 12 elective transplant procedures from home); 34 hospital admissions occurred after referral, compared with 344 before referral. Even when adding in the initial hospital admission after referral for these 179 patients, there was a 35% decrease in total hospital admissions in the 6-month period. The estimated savings in hospital readmission costs after subtracting the initial hospital costs for management was $9,800 per patient.

CONCLUSIONS

Comprehensive heart failure management led to improved functional status and an 85% decrease in the hospital admission rate for transplant candidates discharged after evaluation. The potential to reduce both symptoms and costs suggests that referral to a heart failure program may be appropriate not only for potential heart transplantation, but also for medical management of persistent functional class III and IV heart failure.

Sustained hemodynamic efficacy of therapy tailored to reduce filling pressures in survivors with advanced heart failure

BACKGROUND

During therapy to relieve congestion in advanced heart failure, cardiac filling pressures can frequently be reduced to near-normal levels with improved cardiac output. It is not known whether the early hemodynamic improvement and drug response can be maintained long term.

METHODS AND RESULTS

After referral for cardiac transplantation with initially severe hemodynamic decompensation, 25 patients survived without transplantation to undergo hemodynamic reassessment after 8+/-6 months of treatment tailored to early hemodynamic response. Initial changes included net diuresis, increased ACE inhibitor doses, and frequent addition of nitrates. After 8 months of therapy, early reductions were sustained for pulmonary wedge pressure (24+/-9 to 15+/-5 mm Hg early; 12+/-6 mm Hg late) and systemic vascular resistance (1651+/-369 to 1207+/-281 dynes x s(-1) x cm(-5) early; 1003+/-193 dynes x s(-1) x cm(-5) late). Acute response to doses persisted at reevaluation. Sustained reduction in filling pressures was accompanied by a progressive increase in stroke volume (42+/-10 to 56+/-13 mL early; 79+/-20 mL late), improved functional class, and freedom from resting symptoms. Study design did not control for amiodarone, which was initiated for arrhythmias in 12 patients and associated with greater improvement in cardiac index (1.8 to 3.2 L min(-1) x m(-2) late on amiodarone versus 2.0 to 2.6 L x min(-1) x m(-2), P<.05).

CONCLUSIONS

During chronic therapy tailored to early hemodynamic response in advanced heart failure, acute vasodilator response persists, and near-normal filling pressures can be maintained in patients who survive without transplantation. Stroke volumes at low filling pressures increase further over time. Chronic hemodynamic improvement was accompanied by symptomatic improvement, but the contributions of the monitored hemodynamic approach, increased vasodilator doses, and comprehensive outpatient management have not yet been established.

QT dispersion as a marker of risk in patients awaiting heart transplantation

OBJECTIVES

The objectives of this study were to determine whether a signal-averaged electrocardiogram (SAECG) or measurement of interlead variability of QT intervals on an electrocardiogram (ECG) obtained at the time of wait-listing could provide prognostic value with respect to cardiac death during the waiting period.

BACKGROUND

Because heart transplantation is a life-saving but limited resource, there remains an urgent need to identify those patients at greatest risk of dying while awaiting heart transplantation as part of the strategy to optimize the allocation of donor organs to those in greatest need. This study was undertaken to prospectively identify clinical, ECG or SAECG variables that might predict mortality during the waiting period.

METHODS

Of 108 consecutive patients referred for heart transplant evaluation, 80 were placed on a waiting list, at which time a standard 12-lead ECG and a SAECG were recorded. In this cohort of 80 patients, QT dispersion was characterized from the 12-lead ECG as either the maximal-minimal QT interval (QTDISP) or as the coefficient of variation of all QT intervals (QTCV).

RESULTS

During the 25-month follow-up period (mean time on waiting list, 201 days), the mortality rate was 27%/year, divided equally between heart failure and sudden deaths. No clinical variable identified at entry predicted mortality. QTDISP and QTCV were strong mortality predictors, with a 4.1-fold increase in mortality in patients with QTDISP > 140 ms compared with those patients with QTDISP < or = 140 ms (95% CI 1.1 to 14.9), whereas a QTCV > or = 9% also predicted a 4.1-fold increased risk of death (95% CI 1.4 to 11.8). Although 88% of all SAECGs were abnormal, no patient with a normal SAECG died suddenly during the waiting period.

CONCLUSIONS

Indexes of QT dispersion provide a means of stratifying a patient's risk of dying while awaiting heart transplantation and may help to establish priority on a heart transplant waiting list.

Secular trends in cardiac transplant recipient and donor management in the United States, 1990 to 1994. A multi-institutional study. Cardiac Transplant Research Database Group

BACKGROUND

The growth of the US cardiac transplant waiting list has outpaced the increase in donors, resulting in a widening gap between the number of waiting recipients and available donors. These trends have generated concern that longer waiting times may result in more patients deteriorating to urgent status and that transplanting only patients who are in an advanced state of decompensation will reduce posttransplant survival. Furthermore, the shortage of donors may result in extending the guidelines for donor acceptability to a degree that increases graft failure and posttransplant mortality. We measured these secular trends in the Cardiac Transplant Research Database to provide current data on time-dependent changes in US cardiac transplant practice and survival.

METHODS AND RESULTS

At the time of this analysis, the Cardiac Transplant Research Database included all 2749 patients transplanted from January 1, 1990, to June 30, 1994, in the 25 participating transplant centers. During this 4.5-year period, the median waiting time for recipients who received a transplant increased from 2.7 to 3.5 months (P < .0001), and the proportion of recipients whose status was urgent at transplantation increased from 41% to 60% (P < .0001). Donor ischemic time increased from 150 to 166 minutes (P < .0001), and the proportion of donors requiring pressor support increased from 68% to 85% (P < .0001). Despite these changes in practice, the 1-year survival rate remained constant at 84% during this 4.5-year interval. There was no significant difference in 1-year survival rate between urgent status patients (83%) and nonurgent status patients (85%) (P = .08).

CONCLUSIONS

The widening gap between the number of waiting recipients and the number of donors has resulted in a continuing trend toward transplanting urgent status recipients and to a liberalization of donor acceptance criteria. Despite these changes, posttransplant survival has remained constant.

Heart transplantation: a single-center experience

BACKGROUND

The success of heart transplantation led to the extension of the criteria for both recipients and donors. The aim of the study was to evaluate the experience with this therapeutic approach for end-stage heart failure at a single center.

METHODS

Between April 1986 and January 1996, 1,413 patients were accepted as candidates for heart transplantation. Ventricular assist devices were used as a bridge to transplantation in 173 patients (biventricular assist device in 141 patients and left ventricular assist device in 32 patients). The longest duration of support was 572 days (average, 46 days).

RESULTS

Of the 1,413 patients, 891 underwent heart transplantation (65 children/adolescents and 826 adults; 522 (36%) patients died awaiting a donor heart. The average time spent on the waiting list was 107 days. The average recipient age was 44 years, and the age of donors was extended up to 69 years. Eighty-three patients with ventricular assist devices (48%) subsequently underwent heart transplantation. Twenty-five patients (2.7%) underwent retransplantation. The 30-day mortality rate was 14%, and the overall actual survival at 1, 5, and 10 years was 80%, 59%, and 50%, respectively. Ninety-four percent of patients were in New York Heart Association functional class I or II at 1 year, and 44% returned to work after transplantation.

CONCLUSIONS

Despite the broadening of the selection criteria for both recipients and donors, heart transplantation remains an effective treatment for end-stage heart failure. Nevertheless, this therapeutic approach is severely limited by a considerable disparity between the need and availability of donor organs.

Analysis of deaths in patients awaiting heart transplantation: impact on patient selection criteria

OBJECTIVE

To analyse the clinical characteristics of patients who died on the Stanford heart transplant waiting list and to develop a method for risk stratifying status 2 patients (outpatients).

METHODS

Data were reviewed from all patients over 18 years, excluding retransplants, who were accepted for heart transplantation over an eight year period from 1986 to 1994.

RESULTS

548 patients were accepted for heart transplantation; 53 died on the waiting list, and 52 survived on the waiting list for over one year. On multivariate analysis only peak oxygen consumption (peak VO2: 11.7 (SD 2.7) v 15.1 (5.2) ml/kg/min, P = 0.02) and cardiac output (3.97 (1.03) v 4.79 (1.06) litres/min, P = 0.04) were found to be independent prognostic risk factors. Peak VO2 and cardiac index (CI) were then analysed in the last 141 consecutive patients accepted for cardiac transplantation. All deaths and 88% of the deteriorations to status 1 on the waiting list occurred in patients with either a CI < 2.0 or a VO2 < 12. In those with a CI < 2.0 and a VO2 < 12, 38% died or deteriorated to status 1 in the first year on the waiting list. Patients with CI > or = 2.0 and a VO2 > or = 12 all survived throughout follow up. Using a Cox's proportional hazards model with CI and peak VO2 as covariates, tables were constructed predicting the chance of surviving for (a) 60 days and (b) 1 year on the waiting list.

CONCLUSIONS

These data provide a basis for risk stratification of status 2 patients on the heart transplant waiting list.

Sex differences in patient acceptance of cardiac transplant candidacy

BACKGROUND

The overwhelming majority of cardiac transplant recipients are men. This can be partially explained by the earlier age at which heart failure develops in men. However, an underrepresentation of women also may reflect physician referral or selection biases or differences in patients' access to or acceptance of heart transplantation.

METHODS AND RESULTS

We investigated whether sex bias occurred in the transplant candidate selection process at a single cardiac transplant center. We prospectively evaluated 386 individuals < 70 years of age (295 men, 91 women) referred for management of moderate to severe heart failure and/or cardiac transplant evaluation. Age, race, sex, heart failure type, New York Heart Association class, left ventricular ejection fraction, peak exercise oxygen consumption, disease duration, resting hemodynamic measurements, comorbidity index score, health insurance coverage, and estimated household income were recorded. For patients not accepted for transplantation, the reason for rejection was also obtained. Univariable and multivariable (logistic regression) analyses were performed comparing men and women and patients accepted and those not accepted for cardiac transplantation. Female sex was independently associated with rejection for cardiac transplantation (odds ratio, 2.57; P = .01). However, the reason for rejection (odds ratio, 2.57; P = .01). However, the reason for rejection was more likely to be patient self-refusal for women than for men (29% versus 9%), and female sex was independently associated with patient self-refusal (odds ratio, 4.68; P = .003). When patients who refused transplant were reclassified as accepted for transplant, female sex was no longer associated with nonacceptance. However, lower patient income was associated with nonacceptance for transplant.

CONCLUSIONS

We found no evidence of sex bias in the selection of cardiac transplant recipients at our center. These findings suggest that the underrepresentation of women among cardiac transplant recipients may result, in part, from a sex difference in treatment preference, with a decreased willingness of women to undergo transplantation. The reasons for the difference in acceptance rates between men and women need to be elucidated.

Prognosis in congestive heart failure

Prognostic variables such as the ejection fraction and peak oxygen consumption can be used to place patients with heart failure in risk strata. Some vasodilators have been shown to improve survival at all stages of heart failure with the probability of benefit increasing as the prognosis worsens. Quantitative estimates of survival among groups defined by prognostic variables and treatments should be used to make more informed benefit-to-risk assessments.