Hypertension in Patients with Cardiac Transplantation

Metabolic Syndrome and Heart Transplantation: An Underestimated Risk Factor?

Metabolic Syndrome (MetS), a multifactorial condition that increases the risk of cardio-vascular events, is frequent in Heart-transplant (HTx) candidates and worsens with immunosuppressive therapy. The aim of the study was to analyze the impact of MetS on long-term outcome of HTx patients. Since 2007, 349 HTx patients were enrolled. MetS was diagnosed if patients met revised NCEP-ATP III criteria before HTx, at 1, 5 and 10 years of follow-up. MetS was present in 35% of patients pre-HTx and 47% at 1 year follow-up. Five-year survival in patients with both pre-HTx (65% vs. 78%, p < 0.01) and 1 year follow-up MetS (78% vs 89%, p < 0.01) was worst. At the univariate analysis, risk factors for mortality were pre-HTx MetS (HR 1.86, p < 0.01), hypertension (HR 2.46, p < 0.01), hypertriglyceridemia (HR 1.50, p=0.03), chronic renal failure (HR 2.95, p < 0.01), MetS and diabetes at 1 year follow-up (HR 2.00, p < 0.01; HR 2.02, p < 0.01, respectively). MetS at 1 year follow-up determined a higher risk to develop Coronary allograft vasculopathy at 5 and 10 year follow-up (25% vs 14% and 44% vs 25%, p < 0.01). MetS is an important risk factor for both mortality and morbidity post-HTx, suggesting the need for a strict monitoring of metabolic disorders with a careful nutritional follow-up in HTx patients.

Type A Aortic Dissection in Heart Transplantation Recipients in the United States

BACKGROUND

Type A aortic dissection in heart transplantation recipients is rare and lethal, with limited research beyond case reports. This study aimed to analyze patient characteristics and clinical outcomes of this condition through a US national database.

METHODS

The National Inpatient Sample database (2002-2018) was used to identify all type A aortic dissection in heart transplantation recipients aged >18 years. Incidence was quantified annually. Primary outcomes were in-hospital mortality; secondary outcomes were hospital length of stay and complications.

RESULTS

We identified 78 cases of type A aortic dissection in heart transplantation recipients. Compared with type A aortic dissection patients without a history of solid organ transplantation (N = 70,715), our patients were younger (55.3 vs 60.7 years), less likely female (18.5% vs 33.5%), and more frequently Black or Hispanic (55% vs 23%). They had a greater prevalence of Marfan syndrome (13% vs 3%), congestive heart failure (46% vs 19%), and chronic kidney disease (19% vs 10%), as well as increased in-hospital mortality (30% vs 18%) and a longer hospital length of stay (29.5 vs 13.7 days). They experienced elevated rates of cardiac (57% vs 31%), respiratory (70. % vs 41%), renal (76% vs 30%), and bleeding complications (37% vs 14%).

CONCLUSIONS

Type A aortic dissection in heart transplantation recipients appears to exhibit distinct characteristics and poorer outcomes compared with those in the general population. Heart transplantation recipients with predisposing risk factors warrant heightened attention to help prevent this devastating condition.

Type A aortic dissection following heart transplantation: A case report

BACKGROUND

Cardiac transplantation is considered the standard treatment for refractory end-stage heart failure. Worldwide, 5074 heart transplantations were performed in 2015. About 100 heart transplants are performed at the authors’ center each year. The usual complications of heart transplantation include graft rejection, infection, and graft dysfunction. Aortic dissection after heart transplantation is very rare and is a serious complication that requires a hybrid procedure.

CASE SUMMARY

A 58-year-old female patient was admitted to Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology in July 2020 because of unprovoked low back pain without precipitating causes. Magnetic resonance imaging and computed tomography angiography showed type A aortic dissection with an aberrant right subclavian artery. After admission, urapidil was used to control blood pressure. Ten days later, the patient underwent ascending aortic and aortic arch replacement, subclavian artery reconstruction, and endovascular repair of abdominal and thoracic aortic aneurysms. A cardiopulmonary bypass was established through the right femoral artery and femoral vein. The aberrant right subclavian artery, innominate artery, left common carotid artery, and left subclavian artery were blocked, and the left and right common carotid arteries were cannulated for bilateral cerebral perfusion.

CONCLUSION

The right axillary artery could not be selected for cardiopulmonary bypass intubation because of aberrant right subclavian artery.

Angiotensin-converting enzyme inhibitor therapy after heart transplant: from molecular basis to clinical effects

The use of angiotensin-converting enzyme inhibitors is an important therapy for various cardiovascular diseases, such as hypertension, ischemic heart disease and heart failure. In heart transplant recipients, angiotensin-converting enzyme inhibitors have been demonstrated to be a keystone for the treatment of hypertension with a wide spectrum of pleiotropic molecular effects ranging from improvement of the peripheral vascular system to regulation of the fluid and sodium balance. In addition, angiotensin-converting enzyme inhibitors may be also useful in the prevention of graft failure, cardiac allograft vasculopathy and chronic kidney disease progression. Further tailored multi-center and randomized studies are warranted to confirm the pleiotropic clinical effects of ACEi therapy in HTRs and to support more extended use in daily clinical practice. Finally in the near future, the use of novel pharmacological agents that inhibit the renin-angiotensin-aldosterone system such as the neprylisin inhibitor sacubitril should be investigated in heart transplant recipients. This article is protected by copyright. All rights reserved.

Predictors of Hypertension Development 1 Y After Heart Transplantation

BACKGROUND

Hypertension after heart transplantation (HTx) is common. We investigated predictors of and mechanisms for hypertension development during the first year after HTx, with particular attention toward immunosuppressive agents, reinnervation processes, and donor/recipient sex.

METHODS

Heart transplant recipients (HTxRs) were consecutively enrolled 7 to 12 wk after surgery and followed prospectively for 12 mo. Ambulatory blood pressure recordings and autonomic cardiovascular control assessments were performed at baseline and follow-up. Possible predictors of posttransplant hypertension development were investigated in bivariate linear regression analyses followed by multiple regression modeling.

RESULTS

A total of 50 HTxRs were included; 47 attended the follow-up appointment at 12 mo. Mean systolic and diastolic blood pressure increased significantly during the observational period (systolic blood pressure from 133 to 139 mm Hg, P = 0.007; diastolic blood pressure from 81 to 84 mm Hg, P = 0.005). The blood pressure increment was almost exclusively confined to HTxRs with a female donor heart, doubling the cases of systolic hypertension (from 6 to 13/14; 46% to 93%, P = 0.031) and diastolic hypertension (from 7 to 14/14; 54% to 100%, P = 0.031) in this subgroup. Autonomic cardiovascular control assessments suggested tonically constricted resistance and capacitance vessels in recipients with female donor hearts. Immunosuppressive agents and reinnervation markers were not associated with hypertension development.

CONCLUSIONS

Blood pressures increase during the first year after HTx, with female donor sex as a strong predictor of recipient hypertension development. The underlying mechanism seems to be enhanced peripheral vasoconstriction caused by attenuated cardiovascular homeostasis capabilities. Further studies are needed to confirm the results.

Management of long-term cardiovascular risk factors post organ transplant

PURPOSE OF REVIEW

Cardiovascular disease is one of the leading causes of death in solid organ transplant (SOT) recipients. Early identification of cardiovascular risk factors and their adequate management in this population is key for prevention and improved outcomes.

RECENT FINDINGS

Approximately 80% of SOT present one or more cardiovascular risk factors, with increasing prevalence with time posttransplantation. They are due to the interplay of pretransplant conditions and metabolic consequences of immunosuppressive agents, mainly corticosteroids and calcineurin inhibitors. Among the pharmacological management strategies, statins have shown an important protective effect in SOT.

SUMMARY

Strict surveillance of cardiovascular risk factors is recommended in SOT due to their high prevalence and prognostic implications. Further studies on the best managements strategies in this population are needed.

Exercise training in heart transplantation

Heart transplantation remains the gold standard in the treatment of end-stage heart failure (HF). Heart transplantation patients present lower exercise capacity due to cardiovascular and musculoskeletal alterations leading thus to poor quality of life and reduction in the ability of daily self-service. Impaired vascular function and diastolic dysfunction cause lower cardiac output while decreased skeletal muscle oxidative fibers, enzymes and capillarity cause arteriovenous oxygen difference, leading thus to decreased peak oxygen uptake in heart transplant recipients. Exercise training improves exercise capacity, cardiac and vascular endothelial function in heart transplant recipients. Pre-rehabilitation regular aerobic or combined exercise is beneficial for patients with end-stage HF awaiting heart transplantation in order to maintain a higher fitness level and reduce complications afterwards like intensive care unit acquired weakness or cardiac cachexia. All hospitalized patients after heart transplantation should be referred to early mobilization of skeletal muscles through kinesiotherapy of the upper and lower limbs and respiratory physiotherapy in order to prevent infections of the respiratory system prior to hospital discharge. Moreover, all heart transplant recipients after hospital discharge who have not already participated in an early cardiac rehabilitation program should be referred to a rehabilitation center by their health care provider. Although high intensity interval training seems to have more benefits than moderate intensity continuous training, especially in stable transplant patients, individualized training based on the abilities and needs of each patient still remains the most appropriate approach. Cardiac rehabilitation appears to be safe in heart transplant patients. However, long-term follow-up data is incomplete and, therefore, further high quality and adequately-powered studies are needed to demonstrate the long-term benefits of exercise training in this population.

Functional evidence of low-pressure cardiopulmonary baroreceptor reinnervation 1 year after heart transplantation

PURPOSE

Heart transplantation (HTx) implies denervation of afferent neural connections. Reinnervation of low-pressure cardiopulmonary baroreceptors might impact the development and treatment of hypertension, but little is known of its occurrence. The present prospective study investigated possible afferent reinnervation of low-pressure cardiopulmonary baroreceptors during the first year after heart transplantation.

METHODS

A total of 50 heart transplant recipients (HTxRs) were included and were evaluated 7-12 weeks after transplant surgery, with follow-up 6 and 12 months later. In addition, a reference group of 50 healthy control subjects was examined once. Continuous, non-invasive recordings of cardiovascular variables were carried out at supine rest, during 15 min of 20° head-up tilt, during Valsalva maneuver and during 1 min of 30% maximal voluntary handgrip. In addition, routine clinical data including invasive measurements were used in the analyses.

RESULTS

During the first year after HTx, the heart rate (HR) response to 20° head-up tilt partly normalized, a negative relationship between resting mean right atrial pressure and HR tilt response developed, low-frequency variability of the RR interval and systolic blood pressure at supine rest increased, and the total peripheral resistance response to Valsalva maneuver became stronger.

CONCLUSION

Functional assessments suggest that afferent reinnervation of low-pressure cardiopulmonary receptors occurs during the first year after heart transplantation, partially restoring reflex-mediated responses to altered cardiac filling.

Beta-blocker therapy in heart transplant recipients: A review

Beta-blockers are essential drugs for the treatment of many cardiovascular diseases, such as heart failure, acute and chronic ischemic heart disease, tachyarrhythmias, and hypertension. However, these drugs have not been used in cardiac transplant patients for many years owing to the fear that they could reduce cardiac output and functional capacity. In recent years, however, some evidence has shown that even in cardiac transplanted patients, β-blockers are useful and effective in the treatment of sinus tachycardia, supraventricular and ventricular tachyarrhythmias, left ventricular systolic dysfunction, and arterial hypertension. Furthermore, some data have shown that the use of β-blockers is associated with reduced mortality in heart transplant recipients. In this review, we summarize this evidence with particular emphasis on the practical aspects of the use of β-blockers in post-transplantation patients to promote the use of this important class of drugs in clinical practice.

Autonomic cardiovascular control changes in recent heart transplant recipients lead to physiological limitations in response to orthostatic challenge and isometric exercise

PURPOSE

Heart transplantation causes denervation of the donor heart, but the consequences for cardiovascular homeostasis remain to be fully understood. The present study investigated cardiovascular autonomic control at supine rest, during orthostatic challenge and during isometric exercise in heart transplant recipients (HTxR).

METHODS

A total of 50 HTxRs were investigated 7-12 weeks after transplant surgery and compared with 50 healthy control subjects. Continuous, noninvasive recordings of cardiovascular variables were carried out at supine rest, during 15 min of 60° head-up tilt and during 1 min of 30% of maximal voluntary handgrip. Plasma and urine catecholamines were assayed, and symptoms were charted.

RESULTS

At supine rest, heart rate, blood pressures and total peripheral resistance were higher, and stroke volume and end diastolic volume were lower in the HTxR group. During tilt, heart rate, blood pressures and total peripheral resistance increased less, and stroke volume and end diastolic volume decreased less. During handgrip, heart rate and cardiac output increased less, and stroke volume and end diastolic volume decreased less. Orthostatic symptoms were similar across the groups, but the HTxRs complained more of pale and cold hands.

CONCLUSION

HTxRs are characterized by elevated blood pressures and total peripheral resistance at supine rest as well as attenuated blood pressures and total peripheral resistance responses during orthostatic challenge, possibly caused by low-pressure cardiopulmonary baroreceptor denervation. In addition, HTxRs show attenuated cardiac output response during isometric exercise due to efferent sympathetic denervation. These physiological limitations might have negative functional consequences.

Controversies in the Postoperative Management of the Critically Ill Heart Transplant Patient

Heart transplant recipients are susceptible to a number of complications in the immediate postoperative period. Despite advances in surgical techniques, mechanical circulatory support (MCS), and immunosuppression, evidence supporting optimal management strategies of the critically ill transplant patient is lacking on many fronts. This review identifies some of these controversies with the aim of stimulating further discussion and development into these gray areas.

Controlled arterial hypertension and adverse event free survival rate in heart recipients

Aim.To evaluate the prevalence of arterial hypertension (AH) in heart transplant recipients, and its influence on the risk of adverse events, as the efficacy and safety of antihypertension medications (AHM).

Material and methods.To the study, were consequently included all heart transplant recipients operated in the Shumakov Centre during the years 2013 to 2016 and survived 90 days after orthotopic heart transplantation.

Results.Totally, 353 recipients included, with AH or AHM intake in anamnesis in 62 (17,6%). Within 90 days post-surgery, AH that demanded  for medication therapy was found in 151 (42,8%) patients. In posttransplant AH patients there were the following specific parameters in preoperational period: higher body mass index — 25,7±4,1 vs 24,9±4,4 (р=0,026), blood creatinine concentration — 100,6±62,6 vs 68,8±4,8 (р<0,001), donor heart posterior wall thickness — 11,9±0,8 vs 11,3±0,7 (р=0,034), creatinine concentration in 3 month after operation  — 131,7±101,6 vs 94,1±46,5 (p<0,001). There was relation revealed, of AH development risk with anamnesis of AH and renal failure, as a necessity for renal replacement therapy within 30 days post surgery and episodes of acute antibody-mediated reaction on transplant. In the recipients taking angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (ACEi/ARB) before operation, the survival rate free from adverse events was better than in those taking calcium channel blockers (CCB) (plog-rank=0,042).

Conclusion.The results of the study point on high prevalence of AH in heart recipients. Presence of AH in anamnesis, renal failure, episodes of humoral, but not cellular, reaction to the transplant, and donor heart hypertrophy do significantly increase the probability of AH development after transplantation. Comparison revealed significant benefit of ACEi/ ARB versus CCB as antihypertension medications in either monotherapy or in combination with diuretics.