Combined Heart-Kidney Transplant Versus Sequential Kidney Transplant in Heart Transplant Recipients

ObjectivesIn patients with reduced kidney function there are no established guidelines to suggest combined heart-kidney transplant (HKTx) versus sequential kidney transplant (SKTx) using preoperative value of estimated glomerular filtration (eGFR).MethodsThe United Network for Organ Sharing database was queried from 2000 to 2015 to evaluate survival of HKTx and SKTx population stratified by preoperative eGFR rate <45 mL/min. Aim of the study was to assess the eGFR rate that is most beneficial to perform a concomitant or a SKTx at time of transplant evaluation.ResultsIn our analysis, patients who required SKTx are recipients that, after heart transplantation, developed or worsened kidney insufficiency due to calcineurin inhibitor nephrotoxicity. In recipients with eGFR <30 or dialysis, a total of 545 received HKTx and 80 received SKTx. The median waiting time between heart and kidney transplant in SKTx group was 6 years. The overall post-transplant survival was 81% and 80% and 75% and 59% at 5 and 1 years for the HKTx and SKTx groups, respectively (P = .04). In recipients with eGFR from 30 to 44, a total of 107 received HKTx and 112 received SKTx. The median waiting time between heart and kidney transplant in SKTx group was 4 years. Overall post-transplant survival showed no statistically significant differences in HKTx group (n=107) compared with SKTx group (n=112) and was 90% and 95% at 1 year and 74% and 52% at 5 years, respectively (P = .4) .ConclusionsTo optimize organ and patient survival, eGFR value can be utilized to discern between HKTx versus SKTx in patients with decreased renal function at the time of heart transplantation. Patients with eGFR<30 or in dialysis presented better survival with HKTx, while both SKTx and HKTx are suitable for patients with eGFR between 30 and 45.     

Percutaneous Revascularization Modalities in Heart Transplant Recipients

Accelerated allograft vasculopathy significantly limits the survival of heart transplant recipients. The prevalence of allograft coronary artery disease is as high as 18% by 1 year and 50% by 5 years following heart transplant. Heart failure and sudden cardiac death are the two most common clinical presentations. In heart transplant recipients with severe, discrete focal allograft vascular disease, percutaneous balloon angioplasty is a viable palliative option. However, its application is limited by a significant restenosis rate and progression of allograft disease in nontreated segments. Diffuse disease with tapering of vessels may be approached by debulking devices. Emerging revascularization modalities for focal stenoses and some of the diffuse tapering vessels include coronary stents, rotational atherectomy, various wavelength lasers, and, to a lesser extent, directional atherectomy. Conceivably, stents will reduce restenosis rates related to focal, discrete plaques; yet it is unknown whether they will be efficacious in short- and long-term treatment of diffusely diseased segments affected by allograft disease. Accurate assessment of clinical outcomes and long-term evaluation is imperative prior to acceptance of these devices as fundamental interventional tools for treatment of allograft coronary artery disease. Cathet. Cardiovasc. Intervent. 46:227–237, 1999. © 1999 Wiley-Liss, Inc.     

Ambulatory Blood Pressure Monitoring and Echocardiographic Findings in Renal Transplant Recipients

Hypertension is common in renal transplant recipients (RTRs). Ambulatory blood pressure (BP) monitoring (ABPM) is important in diagnosing hypertension and diurnal BP variation. The authors set out to compare office BP and ABPM measurements to determine diurnal pattern and to evaluate echocardiographic findings in RTRs. ABPM and office BP measurements were compared in 87 RTRs. Echocardiographic evaluation was performed for each patient. The correlations between office and 24‐hour ABPM were 0.275 for mean systolic BP (P=.011) and 0.260 for mean diastolic BP (P=.017). Only 36.8% had concordant hypertension between office BP and ABPM, with a masked hypertension rate of 16.1% and white‐coat effect rate of 24.1%. Circadian BP patterns showed a higher proportion of nondippers (67.8%). Left ventricular mass index was increased in 21.8% of all recipients. There was a significant but weak correlation between office BP and ABPM.     

Echocardiographic Evaluation of Hemodynamics in Patients With Systolic Heart Failure Supported by a Continuous-Flow LVAD

BackgroundHemodynamics assessment is important for detecting and treating post-implant residual heart failure, but its accuracy is unverified in patients with continuous-flow left ventricular assist devices (CF-LVADs).ObjectivesWe determined whether Doppler and 2-dimensional transthoracic echocardiography reliably assess hemodynamics in patients supported with CF-LVADs.MethodsSimultaneous echocardiography and right heart catheterization were prospectively performed in 50 consecutive patients supported by using the HeartMate II CF-LVAD at baseline pump speeds. The first 40 patients were assessed to determine the accuracy of Doppler and 2-dimensional echocardiography parameters to estimate hemodynamics and to derive a diagnostic algorithm for discrimination between mean pulmonary capillary wedge pressure ≤15 versus >15 mm Hg. Ten patients served as a validation cohort.ResultsDoppler echocardiographic and invasive measures of mean right atrial pressure (RAP) (r = 0.863; p < 0.0001), systolic pulmonary artery pressure (sPAP) (r = 0.880; p < 0.0001), right ventricular outflow tract stroke volume (r = 0.660; p < 0.0001), and pulmonary vascular resistance (r = 0.643; p = 0.001) correlated significantly. Several parameters, including mitral ratio of the early to late ventricular filling velocities >2, RAP >10 mm Hg, sPAP >40 mm Hg, left atrial volume index >33 ml/m², ratio of mitral inflow early diastolic filling peak velocity to early diastolic mitral annular velocity >14, and pulmonary vascular resistance >2.5 Wood units, accurately identified patients with pulmonary capillary wedge pressure >15 mm Hg (area under the curve: 0.73 to 0.98). An algorithm integrating mitral inflow velocities, RAP, sPAP, and left atrial volume index was 90% accurate in distinguishing normal from elevated left ventricular filling pressures.ConclusionsDoppler echocardiography accurately estimated intracardiac hemodynamics in these patients supported with CF-LVAD. Our algorithm reliably distinguished normal from elevated left ventricular filling pressures.     

Nonpharmacologic Validation of the Intrinsic Heart Rate in Cardiac Transplant Recipients

Background: The maximum sinus rate during exertion in humans is inversely related to age. However, the sinus rate at rest is quite variable. The intrinsic heart (IHR) following pharmacologic blockade of autonomic tone with propranolol and atropine has been proposed as a test of sinus node function and is related to age by the linear regression equation: IHR = 118.1 – (0.57 × age). Whether this relationship exists for transplanted hearts for which the donor sinus node is denervated has not been determined. Methods: The relationship between the resting heart rate and the age of the donor heart was examined in 103 patients 1 year following orthotopic cardiac transplantation in the absence of rejection or intercurrent illness. Patients receiving beta-blockers, calcium blockers, antiarrhythmic drugs, digitalis, theophylline, or with biopsy evidence of rejection or abnormal coronary arteriograms were excluded from analysis. Results: The recipient age, left ventricular ejection fraction, pulmonary capillary pressure, cardiac index, donor heart ischemic time and cardiopulmonary bypass time did not correlate with the rate of the resting donor sinus node. The resting heart rate was inversely related to age of the donor heart by the linear regression equation: HR = 112.0 – (046 × age). Conclusion: The resting rate of the denervated sinus node is related to donor age with a regression equation that is similar, though slightly slower, than that predicted after pharmacologic autonomic blockade.     

Hypertension Prophylaxis With Omega-3 Fatty Acids in Heart Transplant Recipients

Objectives. This study sought to determine whether omega-3 fatty acids act as hypertension prophylaxis in heart transplant recipients and have an impact on vascular reactivity.Background. Cyclosporine-induced hypertension is probably related to endothelial dysfunction. Suggested vasodilatory mechanisms of omega-3 fatty acids may therefore be particularly beneficial in heart transplant recipients.Methods. Heart transplant recipients were randomized to receive either 4 g of omega-3 fatty acids (treatment group, n = 14) daily or corn oil (placebo group, n = 14) from the fourth postoperative day. Twenty-four hour blood pressure monitoring was performed at day 12 and 1, 2, 3 and 6 months postoperatively. Microvascular endothelium-dependent vasodilation, evaluated by skin laser Doppler perfusion measurements of postocclusive reactive hyperemia, was determined preoperatively and at the end of the study.Results. With comparable characteristics at the time of randomization, blood levels of cyclosporine did not at any point differ between the groups. After 6 months, systolic blood pressure decreased 2 ± 4 mm Hg (mean ± SEM) in the treatment group and increased 17 ± 4 mm Hg in the placebo group (p < 0.01), whereas diastolic blood pressure increased 10 ± 3 and 21 ± 2 mm Hg (p < 0.01), respectively. The decrease in systolic blood pressure was inversely proportional to increases in concentrations of serum eicosapentaenoic and docosahexaenoic acid (p = 0.01). After 6 months, five patients in the treatment group and nine in the placebo group needed additional antihypertensive treatment. Although the endothelial-dependent phase of the reactive hyperemic response remained unchanged in the treatment group, it decreased significantly in the placebo group.Conclusions. Postoperative daily administration of 4 g of omega-3 fatty acids in heart transplant recipients is effective as hypertension prophylaxis, depending on increases in serum eicosapentaenoic and docosahexaenoic acids. Preservation of microvascular endothelial function, demonstrated by a more pronounced response to forearm skin ischemia in the treatment group, may contribute to the hypotensive role of omega-3 fatty acids.(J Am Coll Cardiol 1997;29:1324–31)     

Echocardiography Detects Elevated Left Ventricular Filling Pressures in Heart Transplant Recipients

Diastolic dysfunction is a recognized complication in heart transplant (HTx) recipients that limits exercise capacity and is a risk factor for mortality. We investigated the ability of echocardiography to detect elevated pulmonary capillary wedge pressure (mean PCWP>15 mmHg) in HTx recipients. This retrospective study comprised HTx recipients with echocardiography and right heart catheterization within 24 hours (n = 100, 113 investigations). Echocardiographic assessment was performed using mitral inflow (E/A ratio, deceleration time [DT], isovolumic relaxation time [IVRT]), tissue Doppler (E/E′ lateral) parameters, and the Doppler‐estimated pulmonary artery systolic pressure (Doppler PASP). The right atrial pressure (RAP) was estimated based on size and the effect of respiration or sniffing on the inferior vena cava diameter. Cutoff values were determined from a derivation group (n = 57, receiver operator characteristic curve analysis) and evaluated in a test group (n = 56). Elevated PCWP were found in 38%. The RAP and PCWP were both normal in 58 investigations and elevated in 39 investigations (concordance rate of 86.6%). The presence of signs of increased RAP by echocardiography or with three of five parameters (E/A, DT, IVRT, E/E′ lateral, and Doppler PASP) reaching the cutoff values ruled in elevated PCWP with positive likelihood ratios ranging from 15.3 to 9. With normal RAP by echocardiography or none of the other parameters reaching cutoff values elevated PCWP can be ruled out with negative likelihood ratios ranging from 0.07 to 0.19. In conclusion, elevated PCWP in HTx recipients can be assessed using echocardiography.     

The Presentation and Diagnosis of Coronary Allograft Vasculopathy in Pediatric Heart Transplant Recipients

One of the most important causes for long‐term graft failure in pediatric heart transplant recipients is coronary allograft vasculopathy (CAV). Graft survival is approximately 50% at 5 years postdiagnosis of CAV. CAV can be difficult to detect largely because of its variability in presentation and in the definition of CAV. Making the diagnosis of CAV can be challenging, and to date, the current gold standard test is angiography, which is an expensive and invasive procedure. A number of studies in the pediatric and adult heart transplant literature exist for noninvasive methods of diagnosing CAV, ranging from biochemical markers and echocardiographic techniques to computed tomography and magnetic resonance imaging. In addition, there is evidence to show that hemodynamic and function evaluation of the coronary arteries in transplanted patients may provide diagnostic clues to the potential development of CAV. These methodologies add to the armamentarium that can compliment angiography for the purposes of diagnosis. Clinical suspicion for CAV should be heightened in patients who have had recurrent rejection, new onset arrhythmias, unexplained recurrent chest or abdominal pain, and/or the development of systolic or diastolic dysfunction in the absence of rejection. This review strives to highlight the current literature with respect to the investigations available for the diagnosis of CAV, recognizing that our understanding of this disease process is still currently in evolution.