Pulmonary hypertension in chronic kidney disease: a hemodynamic characterization

Echocardiographic changes after arteriovenous fistula creation in hemodialysis patients

BACKGROUND

Pulmonary hypertension (PH) is common in end-stage renal disease (ESRD) patients and is associated with increased all-cause and cardiovascular mortality in this group. There is scarce data on the long-term effect of arteriovenous fistula (AVF) creation on pulmonary hypertension (PH) and the reflected changes in echocardiographic measurements.

MATERIALS AND METHODS

This is a retrospective study of 54 patients who underwent AVF creation between 2009 and 2014 and with echocardiographic evaluations before and after surgery. We analyzed pairwise changes in right ventricular systolic pressure (RVSP), right atrial pressure (RAP) during systole, left ventricular mass (LVM), tricuspid regurgitation (TR), mitral E/E' ratio, and ejection fraction (EF), as well as the factors that predicted change in RVSP after surgery.

RESULTS

The median time for the preoperative echocardiogram was 0.3 years (interquartile range (IQR) 0.2 - 0.7 years) prior to AVF creation, while the follow-up echo was done 1.3 (0.6 - 2.1) years after surgery. 67% of the patients had RVSP > 37 mmHg at baseline. There was a significant reduction in RVSP after AVF creation compared to baseline (median 33 (IQR 26 - 43) vs. 46 mmHg, p = 0.0015), with 59% of the patients experiencing a decrease and 19% remaining stable. There were also significant decreases in LVM (201 (143 - 256) vs. 215 (163 - 276), p = 0.045) and RAP systole (10 (10 - 15) vs. 3 (3 - 8); p < 0.001) after surgery. Higher preoperative weight (p = 0.038) and RVSP (p = 0.006), and use of loop diuretics (p = 0.015) were significantly associated with improvement in RVSP after AVF creation.

CONCLUSION

Our results suggest that AVF creation is associated with a significant reduction or stable measurements of RVSP in the ESRD population, likely due to an improvement in volume status.

Clinical outcomes and echocardiographic characteristics between African American and Caucasian patients with acute pulmonary embolism

Background

Despite socioeconomic disparities, no association between clinical presentation and poor outcomes explains a higher mortality in African Americans with pulmonary embolism (PE). The objective is to identify the co-morbidities and echocardiographic characteristics associated with increased mortality in African American patients.

Methods

This is a cross-sectional study of Caucasian or African American patients with PE diagnosed between October 2015 and December 2017 at University of Maryland Medical Center. The outcomes were in-hospital death, length of stay, and bleeding.

Results

There were 303 African Americans and 343 Caucasians. Caucasians were older ( p = 0.007), males ( p = 0.01) with history of coronary artery revascularization (CABG ( p = 0.001), coronary stents ( p = 0.001)), trauma ( p = 0.007), and/or recent surgeries ( p = 0.0001). African Americans exhibited higher rates of diabetes ( p = 0.01), chronic kidney disease ( p = 0.0005), and smoking ( p = 0.04). Severity of PE was similar between groups and there was no difference in clot burden size. African Americans had more right ventricular strain on Computer Tomography ( p = 0.001) and echocardiogram ( p = 0.004); also, underfilled left ventricles ( p = 0.02) and higher right ventricular systolic pressures ( p = 0.001). There was no difference in hospital mortality (7.1% vs. 7.9%, p = 0.71), length of stay (13.1 ± 16.7 vs 12.8 ± 14.9, p = 0.80) and bleeding (9.0% vs.8.3%. p = 0.72). Mortality was higher in African Americans who received advanced therapies (3.8% vs. 18.8%, p = 0.02). The risk of death increased with age (OR 1.04; 95%CI 1.020–1.073) and with advanced therapies (OR 2.43; 95%CI 1.029–5.769).

Conclusions

Differences in co-morbidities, radiologic findings, and echocardiographic characteristics that may contribute to higher mortality in African American patients, specifically those receiving advanced therapies.

Breathlessness and Respiratory Disability After Kidney Transplantation

BACKGROUND

Dyspnea is a common symptom in patients with end-stage kidney disease being treated with dialysis. This study aimed to ascertain the level of respiratory disability in patients after kidney transplantation through assessing a cohort of kidney allograft recipients for respiratory compromise and thereby identifying a potential target for therapeutic intervention.

METHODS

Kidney transplant recipients who were under active observation in a single tertiary referral center were invited to take part in this prevalence study at the time of clinic follow-up. All patients agreed to take part in the study, which involved completing a Medical Research Council (MRC) dyspnea scale, completing the St George's Respiratory Questionnaire, and performing basic spirometry. An MRC score of ≥2 and/or a forced expiratory volume in 1 second <90% predicted prompted formal clinical assessment by a respiratory physician.

RESULTS

This study enrolled 103 patients; 35% of all patients reported breathlessness, and 56% of all patients warranted formal respiratory medicine review. After completion of their investigations, 33 patients were found to have an underlying condition accounting for their symptoms.

CONCLUSION

Our study highlights the issues of respiratory disability and breathlessness in patients who have undergone kidney transplantation. Although extensive cardiologic evaluation is performed routinely and can rule out many causes of dyspnea, respiratory assessment is not a preoperative prerequisite. This study could suggest that a formal pulmonological evaluation and basic spirometry should be part of the pretransplant evaluation of the kidney transplant recipient.

Association of Pulmonary Hypertension With Inflammatory Markers and Volume Status in Hemodialysis Patients of End-Stage Renal Disease

Background and objectives

Pulmonary hypertension (PH) is an independent risk factor for increased mortality, especially in patients undergoing hemodialysis (HD), but the mechanism of its development is unknown. This study aimed at evaluating volume overload and inflammation as potential variables to cause its development in patients undergoing maintenance hemodialysis.

Materials and methods

This was an observational cross-sectional study conducted on patients undergoing hemodialysis at a tertiary hospital in northern India. Patients of end-stage renal disease, aged 18 years or more, on maintenance hemodialysis for over two months were included in the study. The patients were divided into two groups based on the presence or absence of PH, determined by measuring systolic pulmonary arterial pressure (SPAP). The severity of PH was defined as: mild (SPAP 35-45 mmHg), moderate (SPAP 46-55 mmHg), and severe (SPAP> 55mmHg). The two groups were evaluated for demographic variables, type of vascular access, biochemical parameters, and markers of inflammation and fluid overload. Data between the two groups were compared statistically.

Results

This study included a total of 82 patients showing the prevalence of PH to be 25.6% with a men-to-women ratio of 2:1. Out of 21 cases of PH, mild PH was found in seven (33.3%) cases, moderate in 14 (66.7%), and cases with severe PH were none. The two groups differed significantly in ejection fraction and markers of inflammation and volume status. Laboratory data associated with PH were alpha-1-acid glycoprotein (p<0.05) and pro-b-type natriuretic peptide (p <0.05).

Conclusion

The present study showed higher levels of inflammatory markers alpha-1-acid glycoprotein and pro-b-type natriuretic peptide and lower levels of ejection fraction in patients undergoing HD, indicating a significant association with PH.

Association of Pulmonary Hypertension With End-Stage Renal Disease Among the Obese Population

Introduction

Pulmonary hypertension (PH) is a known complication that occurs in patients of end-stage renal disease (ESRD) that have an arteriovenous fistula (AVF) for hemodialysis (HD). It is defined as pulmonary artery pressure (PAP) of greater than 30 mmHg on echocardiography. The presence of PH in ESRD is an independent risk factor and decreases the survival likelihood among HD patients. Unexplained PH is frequently seen in ESRD following AVF.

Obesity can lead to various complications, such as sleep apnea, cardiac complications, pulmonary hypertension, and mortality. Data on the prevalence of coexisting PH and obesity are scarce.

Obese patients often have increased albumin excretion rates (AER) that can lead to early renal impairment and an increase in intraglomerular pressure, which may increase the risk of cardiovascular (CV) morbidity and mortality.

Therefore, the study aimed to evaluate and compare the associated PH and obesity separately and collectively among ESRD patients.

Methods

This comparative cross-sectional study was conducted in a tertiary care public sector hospital with the approval of the medical ethics review board committee.

The study enrolled all consecutive patients with ESRD as defined by having an estimated glomerular filtration rate (GFR) of <15 mL/min/1.7 3 m² from April 2017 till March 2019, who presented to our facility. These patients underwent dialysis twice or thrice a week, each session lasting three to four hours approximately. On initial encounter, trans-thoracic echocardiography (TTE) was done by the cardiologist to diagnose pulmonary hypertension.

In addition, body mass index (BMI) was calculated for all patients, and the patients were categorized into underweight, normal, overweight, or obese. All patients underwent post-dialysis TTE at one hour or when patients were at the optimal dry weight. Systolic PAP and ejection fraction were measured, and pulmonary hypertension was defined as a PAP of 30 mmHg or greater on TTE.

ESRD patients that were diagnosed with PH prior to hemodialysis or had primary PH were excluded from the study. Only ESRD patients developing secondary PH after hemodialysis were included in the study.

The chi-square test was used to see the correlation of gender, ambulation status, smoking status, obesity, pulmonary hypertension, body mass index (BMI), and pulmonary hypertension and obesity combined on the final outcome. A p-value of 0.05 was considered significant. Odds ratio (OR) and relative risk (RR) were calculated for pulmonary hypertension and obesity combined, obesity, and pulmonary hypertension in the final outcome.

Results

The study enrolled 204 patients with a mean age of 46.23 (±20.45 SD) having higher female participation of 108 (52.9%), whereas 96 (47.1%) were males. The average weight of the cohort was 66.78 kg (±22.98 SD) with a mean BMI of 29.91 kg/m² (±13.29SD), 52 (25.5%) patients were underweight, 40 (19.6%) had a normal BMI, 29 (14.2%) were overweight, and 83 (40.7%) patients were obese.

Pulmonary hypertension and obesity combined were observed in 48 (23.5%) of the cases and there was a 4.60 relative risk of death among these individuals, with an odds ratio of 13.35 and a p-value of 0.00.

Conclusion

The study shows a strong synergistic effect of pulmonary hypertension and obesity towards the final survival outcome in ESRD patients who are on hemodialysis.

Preoperative Noncoronary Cardiovascular Assessment and Management of Kidney Transplant Candidates

The pretransplant risk assessment for patients with ESKD who are undergoing evaluation for kidney transplant is complex and multifaceted. When considering cardiovascular disease in particular, many factors should be considered. Given the increasing incidence of kidney transplantation and the growing body of evidence addressing ESKD-specific cardiovascular risk profiles, there is an important need for a consolidated, evidence-based model that considers the unique cardiovascular challenges that these patients face. Cardiovascular physiology is altered in these patients by abrupt shifts in volume status, altered calcium-phosphate metabolism, high-output states (in the setting of arteriovenous fistulization), and adverse geometric and electrical remodeling, to name a few. Here, we present a contemporary review by addressing cardiomyopathy/heart failure, pulmonary hypertension, valvular dysfunction, and arrhythmia/sudden cardiac death within the ESKD population.

Patient Selection for Kidney Transplant

The incidence of end-stage renal disease has continued to increase. Similarly, the number of patients living with a functioning renal allograft has also increased. Transplantation has improved with advances in surgical techniques, immunosuppression, and better control of comorbid conditions. Transplantation is transformative and offers the greatest potential for restoring a healthy, productive, and durable life to appropriately selected patients. This article describes factors to address in selection of renal transplant candidates and discusses commonly encountered perioperative events. Paramount to selecting appropriate candidates is the collaboration between a multidisciplinary team focused on a systematic process guided by protocols and common practices.