Impaired myocardial energetics limits cardiac functional reserve and leads to exercise-induced pulmonary congestion in heart failure with preserved ejection fraction

Background

Abnormal cardiac mitochondrial function and energetics may be a unifying feature in the pathogenesis of heart failure with preserved ejection fraction (HFpEF). Transient pulmonary congestion during exercise is emerging as an important determinant of reduced exercise capacity and symptoms in patients with HFpEF.

Purpose

We sought to determine if impaired myocardial energetics limits cardiac exercise reserve and leads to exercise-induced pulmonary congestion in HFpEF.

Methods

42 patients across the spectrum of diastolic dysfunction and HFpEF (controls n=10; type 2 diabetes (T2DM) n=9; HFpEF n=14; severe diastolic dysfunction due to cardiac amyloid n=9) (Fig. 1a) underwent assessment of cardiac energetics (myocardial phosphocreatine to adenosine triphosphate ratio, PCr/ATP) and function using cardiovascular magnetic resonance (CMR) imaging and echocardiography, and lung-water using a novel pulmonary proton-density MR sequence. Studies were performed at rest and during exercise (20W for 6 minutes) using a CMR-ergometer.

Results

Paralleling the stepwise decline in diastolic function across the groups (E/e' ratio, p<0.0001) was an increase in NT-pro BNP (p<0.0001, Fig. 1b) and reduction in PCr/ATP (control 2.00 [1.86,2.15], T2DM 1.71 [1.61,1.91], HFpEF 1.66 [1.44,1.89], amyloid 1.30 [1.16,1.53], p<0.0001, Fig. 1c). During exercise, there was progressive blunting of left ventricular (LV) diastolic filling (p<0.0001) (Fig. 2a-b), left atrial (LA) dilatation (p<0.0001), failure of RVEF augmentation (p=0.003), RV-PA uncoupling (RV stroke volume to end-systolic volume (SV/ESV) ratio, p=0.0002), and right atrial (RA) dilatation (p<0.0001) across the groups (Fig. 2b). LV diastolic filling (r 0.41, p=0.008), LA dilatation (r −0.35, p=0.03), RVEF augmentation (r 0.46, p=0.003), RV-PA uncoupling (r 0.36, p=0.02), and RA dilatation (r −0.68, p<0.001) during exercise were strongly linked with impaired myocardial energetics (Fig. 2b).

The novel pulmonary proton-density sequence provided images that scaled linearly with water content (validated using a water-doped sponge phantom; r 0.98, p<0.0001), and revealed a progressive increase in lung water signal/pulmonary congestion (Fig. 2c) post-exercise (p<0.0001) across the groups (controls: +0.25% [−1.8, 3.1], p=0.82; T2DM: +0.8% [−1.7, 1.9], p=0.82; HFpEF: +4.4% [0.5, 6.4], p=0.002; amyloid: +6.4% [3.3, 10.0], p=0.004). Pulmonary congestion was associated with impaired LV diastolic filling (r −0.32, p=0.04), RV-PA uncoupling (r −0.39, p=0.01) and RA dilatation (r 0.4, p=0.01) during exercise, and impaired myocardial energetics (r −0.36, p=0.02).

Conclusion

A gradient of myocardial energetic deficit exists across the spectrum of HFpEF. This energetic deficit is related to markedly abnormal cardiac exercise responses, which leads to transient pulmonary congestion. The findings support an energetic basis for impaired cardiac reserve and exercise-induced pulmonary congestion in HFpEF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Baseline clinical and CMR parametersExercise cardiopulmonary parameters

Left Ventricular Aneurysm Perforating into the Right Ventricle: A Rare Complication of a Small Side Branch Occlusion after Elective Percutaneous Coronary Intervention

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LV aneurysm formation and VSR complicated elective PCI.

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This rare pathology occurred after occlusion of a <1-mm diagonal artery.

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Multimodality imaging was integral to correct diagnosis.

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Open surgery is the definitive management of postinfarction VSR when possible.

Drug-Eluting Stents Versus Coronary Artery Bypass Grafts for Left Main Coronary Disease: A Meta-Analysis and Review of Randomised Controlled Trials

BACKGROUND

Revascularisation of left main coronary artery (LMCA) disease can be potentially managed with percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG). Recent randomised controlled trial (RCT) data have added to the literature on this subject and this meta-analysis aims to assess the state of the data to assist in guiding patient treatment decisions.

METHODS

A systematic literature search of Cochrane Library, EMBASE, OVID, and PubMed Medline was performed. Randomised controlled trials of patients with LMCA disease undergoing PCI with drug eluting stents or CABG were included. Clinical outcomes and adverse events were assessed and analysed.

RESULTS

Four suitable RCTs of adequate quality and follow-up were identified. The incidence of major adverse cardiac and cerebrovascular events (MACCE) at 3 to 5 years of follow-up was significantly increased with PCI compared to CABG (23.3% vs 18.2%, OR 1.37; 95% CI: 1.18-1.58; p=<0.0001; I²=0%) and was largely driven by more repeat revascularisation procedures among patients treated with PCI. There was no statistically significant difference in rates of mortality, myocardial infarction or stroke (either individually or when these outcomes were combined as a composite endpoint).

CONCLUSIONS

Coronary artery bypass grafting and PCI both represent reasonable treatment modalities for LMCA disease in appropriately selected patients. However, where CABG is feasible it offers superior long-term freedom from repeat revascularisation. Longer-term follow-up is required to further clarify the durability of mortality outcomes, especially in patients treated with PCI.

Responses to a fourth dose of Haemophilus influenzae type B conjugate vaccine in early life

OBJECTIVE

To describe the immune response of preterm infants, with a reduced response to primary Haemophilus influenzae type B (Hib) immunisation, to a fourth dose of Hib conjugate vaccine given in early life.

DESIGN

Prospective observational study.

SETTING

Five Wessex Neonatal Units.

PATIENTS

Infants born at < 32 weeks and immunised with three doses of combined acellular pertussis-Hib vaccine, with a Hib IgG geometric mean concentration (GMC) < 1.0 microg/ml after these primary immunisations.

INTERVENTIONS

An additional fourth dose of Hib conjugate vaccine given before 1 year of age. Blood taken to assess Hib IgG concentration and avidity after immunisation.

MAIN OUTCOME MEASURES

Hib IgG GMC and avidity index.

RESULTS

Ninety six infants (mean gestational age at birth 29.1 weeks) received a fourth dose of Hib at a mean age of 7.8 months. Hib IgG GMC after the primary immunisations was 0.17 microg/ml (95% confidence interval (CI) 0.14 to 0.20) rising to 4.68 microg/ml (95% CI 3.36 to 6.57) after the fourth dose (p < 0.0001). The IgG response to the fourth dose correlated positively with the response after the primary immunisations (p < 0.001). Hib IgG geometric mean avidity index (GMAI) after the primary immunisations was 30.87 (95% CI 20.40 to 46.73). This increased to 124.73 (95% CI 109.93 to 141.51) after the fourth dose (p < 0.0001).

CONCLUSION

Preterm infants with very low IgG responses to Hib after primary immunisations with a combined acellular pertussis-Hib vaccine mount a good response to a fourth dose of Hib. This study suggests that all infants will benefit from a fourth dose of Hib, regardless of the age at which it is given.

Acellular pertussis vaccine given by accelerated schedule: response of preterm infants

OBJECTIVE

To describe the immune response of preterm infants to a diphtheria/tetanus/three component acellular pertussis (DTaP) vaccine, under an accelerated schedule, and the effects of steroids on this response. To compare responses with those of term infants.

DESIGN

Prospective observational study.

SETTING

Five Wessex neonatal units; Hertfordshire immunisation clinics.

PATIENTS

Infants born at < 32 weeks; term controls.

INTERVENTIONS

DTaP-Haemophilus influenzae type b vaccine given at 2, 3, and 4 months. Blood taken to assess antibody responses to vaccines.

MAIN OUTCOME MEASURES

IgG geometric mean concentrations (GMC) to vaccines.

RESULTS

A total of 130 preterm (mean gestational age 29.1 weeks) and 54 term infants were recruited. After the third immunisation, preterm infants had similar GMCs to controls to diphtheria, tetanus, filamentous haemagglutinin (FHA), and pertactin (PRN), but a significantly lower GMC to pertussis toxin (PT). Responses to tetanus and PRN increased with age at the third immunisation, and those to tetanus, FHA, PRN, and PT increased with gestational age at birth. Response to tetanus correlated negatively with the number of doses of antenatal steroids received. There was no association between responses and postnatal steroids.

CONCLUSION

When immunised with a combined acellular pertussis- H influenzae type b vaccine under an accelerated schedule, IgG GMC of preterm infants to PT was reduced. GMCs to tetanus, FHA, PRN, and PT increased with gestational age at birth, and GMCs to tetanus and PRN increased with age at the third immunisation. There is, however, no benefit in delaying immunisation. Anti-tetanus IgG decreased with increasing number of doses of antenatal steroids. There was no effect for postnatal steroids.

Immune response of premature infants to meningococcal serogroup C and combined diphtheria-tetanus toxoids-acellular pertussis-Haemophilus influenzae type b conjugate vaccines

To determine the immune response of premature infants to meningococcal serogroup C capsular polysaccharide (MCC) and combined diphtheria-tetanus toxoids-acellular pertussis-Haemophilus influenzae type b (DTaP-Hib) conjugate vaccines, 105 infants born at <32 weeks' gestation had Hib IgG geometric mean concentrations (GMCs) and MCC serum bactericidal antibody (SBA) geometric mean titers (GMTs) measured 1 month after the third immunization. Term infants served as control subjects. Premature infants had Hib GMCs of 0.27 microg/mL, with 21% achieving GMCs >1.0 microg/mL, compared with 0.81 microg/mL and 46% in term infants (P<.001 and P=.003, respectively). The MCC SBA GMT was 398, with 99% achieving an SBA > or =8, compared with 380 and 98% in term infants (P=.84 and P=1.0, respectively). Hib IgG was associated with age at third immunization (P<.001). When combined with the DTaP vaccine used in this study, the Hib GMC of premature infants was extremely low. The SBA GMT to MCC was similar to that of term infants.