Association of anaemia on heart failure and left ventricular function: A bidirectional Mendelian randomization study

AIMS

Observational studies have suggested that anaemia is associated with an increased risk of heart failure (HF). But the potential causal association is not clear. We aimed to investigate the association between anaemia and HF risk.

METHODS AND RESULTS

A Mendelian randomization (MR) analysis was performed to confirm the causal association of anaemia with the risk of HF and left ventricular structure and function. Furthermore, a reverse-direction MR analyses was conducted to assess the causal effect of HF on anaemia. The MR analysis indicated that genetically predicted anaemia is associated with the increased risk of HF (meta: odd ratio (OR) = 1.12; 95% confidence interval (CI) [1.04, 1.20]; P = 0.002), and left ventricular mass index (β = 1.051; 95% CI [0.384, 1.718]; P = 0.002), left ventricular mass (β = 2.063; 95% CI [0.578, 3.547]; P = 0.006), left atrial minimum volume (β = 0.076; 95% CI [0.008, 0.143]; P = 0.028), and left atrial maximum volume (β = 0.090; 95% CI [0.023, 0.157]; P = 0.009). In the reverse-direction MR analyses, we found that genetic susceptibility to HF was significantly associated with the increased risk of anaemia (meta: OR = 1.40; 95% CI [1.24, 1.59]; P = 1.79 × 10-7 ).

CONCLUSIONS

This MR study supports the genetic evidence that there is bidirectional causality between anaemia and the risk of HF as well as anaemia may cause left ventricular hypertrophy and enlargement of the left atrium. Considering the adverse causal effects between the two diseases, more attention should be paid to the prevention and treatment of anaemia in patients with HF.

Surviving Critical Low Hemoglobin Levels and Pica

Iron deficiency is the most common nutritional deficiency. Pica is commonly associated with iron deficiency anemia (IDA). A case of a 40-year-old female who presented with a critical record of low hemoglobin (Hgb) (1.6 g/dL) with severe iron deficiency and pica with no lasting deficits despite such low hemoglobin is discussed in this article. The patient presented to the emergency room with complaints of weight loss, weakness, palpitation, fatigue, dysphagia, and on-and-off vomiting for about a year and severe menorrhagia for about one and a half years. She also has had pica for the past several years where she eats and chews toilet paper. Several of her female family members also have pica. She was found to have critically low hemoglobin of 1.6 g/dL and serum iron of 8 ug/dL and ferritin of less than 1 ng/mL. The patient was treated with six units of packed red blood cells and IV and oral iron supplementation. She was discharged with a hemoglobin of 7.3 g/dL. She was later found to have a 9.6 cm uterine mass that is consistent with leiomyoma (fibroid) in transvaginal ultrasound and is following up with a gynecologist for the definitive management. She did not have lasting deficits from the critically low hemoglobin and has stopped engaging in pica behavior.

Left ventricular hypertrophy in pediatric patients on maintenance dialysis: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

BACKGROUND

Cardiovascular disease is the leading cause of death in pediatric patients with kidney failure. Left ventricular hypertrophy (LVH) is recognized as the most common cardiovascular abnormality in these patients. There remains a paucity of longitudinal studies evaluating LVH during maintenance dialysis in children. NAPRTCS has collected echocardiographic data of pediatric maintenance dialysis patients since 2013 and is one of the largest registries to assess longitudinal changes in LVH.

METHODS

Patients aged 1-18 years with echocardiographic data and without underlying structural cardiovascular diseases were included. LVH was defined as left ventricular mass index (LVMI, height-indexed) > 95th percentile for age and sex. Univariate and multivariable logistic regression was performed to assess risk factors for LVH at baseline. Generalized estimating equation was used to assess risk factors of changes in LVH during maintenance dialysis.

RESULTS

A total of 518 patients had echocardiographic data available for analysis during time on maintenance dialysis. Of 179 patients with baseline echocardiography (within 30 days of dialysis initiation), 67% had LVH. In multivariable logistic regression adjusted for age, race, and sex, uncontrolled hypertension (OR 9.4, 95% CI 2.8-31) and anemia (OR 2.3, 95% CI 1.0-5.3) were associated with LVH at baseline. Prevalence of LVH remained high at 40-50% during follow-up. Controlled and uncontrolled hypertension as well as phosphorus level were independently associated with increased likelihood of LVH during maintenance dialysis.

CONCLUSIONS

LVH is prevalent in pediatric patients at dialysis initiation and remains prevalent during follow-up. Hypertension is the strongest risk factor for LVH in children on maintenance dialysis. A higher resolution version of the Graphical abstract is available as Supplementary information.

Association of central arterial blood pressure and left ventricular hypertrophy in patients with chronic kidney disease

AIMS

In the general population, central arterial blood pressure has proved to be more closely related to left ventricular hypertrophy (LVH) than brachial arterial blood pressure. We aimed to investigate whether this relationship was true in patients with chronic kidney disease (CKD).

METHODS

In this retrospective study, we reviewed the medical records of 289 adult patients with CKD from the Zhejiang Provincial People's Hospital in Zhejiang, China. Demographic, echocardiographic and brachial and central blood pressure parameters were retrieved from medical records. Central blood pressure was measured using the SphygmoCor® CvMS (AtCor, Australia) device and its corresponding software. Multivariate logistic regression analyses were performed to identify independent predictors of LVH. Receiver operating characteristic curves were used to determine the ability of central and brachial blood pressure to predict LVH.

RESULTS

The left ventricular mass index was positively associated with both central and brachial blood pressures. However, multiple logistic regression analysis demonstrated that a central pulse pressure (CPP) ≥ 58 mm Hg was an independent risk factor for LVH (OR = 5.597, 95%CI 2.363-13.259, p < .001). Brachial pulse pressure is not superior to CPP in predicting LVH (area under the curve [AUC] = 0.695, 95%CI 0.634-0.756, p < .001 vs. AUC = 0.687, 95%CI: 0.626-0.748, p < .001, respectively; p = .4824).

CONCLUSION

Our results suggested that, similarly to the general population, CPP is a better parameter for predicting the occurrence of LVH in patients with CKD.