Myocardial tissue characterisation and detection of myocardial oedema by cardiovascular magnetic resonance in women with pre-eclampsia: a pilot study.

BACKGROUND: Pre-eclampsia is characterised by increased left ventricular wall thickness on transthoracic echocardiography (TTE). This is assumed to be myocardial hypertrophy, however TTE cannot determine myocardial structure which may be muscle, oedema or fibrosis. Given the high incidence of peripheral oedema in pre-eclampsia, we hypothesised that increased thickness could represent oedema. Cardiovascular magnetic resonance (CMR) characterises myocardial tissue, differentiating between hypertrophy, oedema and fibrosis. This pilot study was designed to characterise myocardial composition using CMR in pregnant women (healthy or with pre-eclampsia) and to compare cardiac output and left ventricular mass using TTE and CMR. METHODS: Thirty-six women (31 healthy, five with pre-eclampsia) underwent TTE and CMR and left ventricular mass was assessed applying standard definitions. Myocardial signal intensities were measured from left ventricular segments and compared to serratus anterior muscle to determine global myocardial signal intensity. Myocardial oedema was defined as a myocardial:skeletal signal intensity ratio >1.9. Agreement between devices for cardiac output and left ventricular mass, and inter- and intra-observer measurements used Bland Altman methodology, calculating the agreement tolerable interval: >1.5 is unacceptable, 1.0-1.5 is marginal and <1.0 is acceptable agreement. RESULTS: Myocardial oedema was present in two (40%) pre-eclamptic women but no healthy women (P=0.017). Agreement for cardiac output was acceptable, for left ventricular mass marginal, and for inter- and intra-observer measurements acceptable. CONCLUSIONS: Cardiovascular magnetic resonance was used to characterise the myocardial tissue in women with pre-eclampsia. Data suggest that some women with pre-eclampsia have myocardial oedema rather than hypertrophy.

Physiologic determinants of exercise capacity in patients with different types of right-sided regurgitant lesions: Ebstein's malformation with tricuspid regurgitation and repaired tetralogy of Fallot with pulmonary regurgitation.

BACKGROUND: Exercise capacity relates to right ventricular (RV) volume overload in congenital heart disease and may improve after surgery. We herewith investigate the relation between exercise capacity, cardiac index, and RV volume overload due to tricuspid regurgitation (TR) in Ebstein's malformation and pulmonary regurgitation (PR) after repair of tetralogy of Fallot (rToF). METHODS: We measured cardiac index and tricuspid/pulmonary regurgitant fraction by cardiovascular magnetic resonance in patients with Ebstein's malformation (n = 40) or rTOF (n = 53) with at least moderate TR/PR and 24 healthy controls. Exercise tolerance was determined by peak oxygen consumption (peak VO2) during cardiopulmonary exercise testing. RESULTS: TR and PR fraction were similar in Ebstein and rTOF patients (43 ± 17% versus 39 ± 12%, respectively). Cardiac index was reduced in Ebstein (2.7 ± 0.6L/min/m(2) compared to controls 3.5 ± 0.9L/min/m(2), p < 0.001) but not in rToF patients (3.2 ± 0.5L/min/m(2)). Multiple regression analysis revealed a significant correlation between peak VO2 and cardiac index in Ebstein. Furthermore, peak VO2 correlated with peak heart rate in both groups but not with regurgitation fraction. CONCLUSIONS: Despite comparable amounts of regurgitation from a right sided heart valve in patients with Ebstein and rToF, reduction of cardiac index was observed only in the former group. Greater physiologic complexity and adverse ventricular interaction with chronotropic incompetence in Ebstein's malformation may account for this.

Prevalence and prognostic implication of restenosis or dilatation at the aortic coarctation repair site assessed by cardiovascular MRI in adult patients late after coarctation repair.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is ideal for assessing patients with repaired aortic coarctation (CoA). Little is known on the relation between long-term complications of CoA repair as assessed by CMR and clinical outcome. We examined the prevalence of restenosis and dilatation at the repair site and the long-term outcome in patients with repaired CoA. METHODS AND RESULTS: CMR imaging and clinical data for adult CoA patients (247 patients aged 33.0 ± 12.8 years, 60% male), were analyzed. The diameter of the aorta at the repair site was measured on CMR and its ratio to the aortic diameter at the diaphragm (repair site-diaphragm ratio, RDR) was calculated. Restenosis (RDR≤70%) was present in 31% of patients (and significant in 9% [RDR<50%]), and dilatation (RDR>150%) in 13.0%. A discrete aneurysm at the repair site was observed in 9%. Restenosis was more likely after resection and end-end anastomosis, whereas dilatation after patch repair. Systemic hypertension was present in 69% of patients. Of the hypertensive patients, blood pressure (133 ± 20/73 ± 10 mm Hg) was well controlled in 93% with antihypertensive therapy. Mortality rate over a median length of 5.9 years was low (0.69% per year, 95% CI: 0.33-1.26), but significantly higher than age-matched healthy controls (standardised mortality ratio 2.86, CI 1.43-5.72, p<0.001). CONCLUSION: Restenosis or dilatation at the CoA repair site as assessed by CMR is not uncommon. Medium term survival remains good, however, albeit lower than in the general population. Life-long follow-up and optimal blood pressure control are likely to secure a good longer term outlook in these patients.

Impact of aortic stenting on peripheral vascular function and daytime systolic blood pressure in adult coarctation.

OBJECTIVES: To determine the relation of ambulatory systolic blood pressure to aortic obstruction and more extensive vascular dysfunction, assessed by central aortic, peripheral conduit arterial and resistance vessel function. METHODS: 12 adults (5 native, 7 recoarctation) were studied before, and 2 weeks and 6 months after aortic stenting. Systolic blood pressure was measured during normal daily living by 24-hour ambulatory monitoring. Central aortic function was assessed by pulse wave analysis (augmentation index). Brachial artery flow-mediated dilatation and dilatation in response to 25 mug of sublingual glyceryl trinitrate was assessed by ultrasound to measure peripheral conduit arterial and resistance vessel function. Baseline vascular measures were compared with those of 12 matched controls. RESULTS: Patients had a higher augmentation index, impaired endothelium-dependent and -independent dilatation, and forearm vascular resistance (p<0.02). After successful gradient relief by stenting, daytime ambulatory systolic blood pressure (151 (134, 166) mm Hg vs 138 (130, 150) mm Hg, p = 0.01) and the augmentation index (26 (15, 34) vs 23 (13, 30), p = 0.03) fell progressively over 6 months, but did not completely normalise. Endothelium-dependent and -independent dilatation, and forearm vascular resistance remained unchanged and impaired. CONCLUSION: Relief of aortic obstruction is associated with improvement in central aortic function and results in reduction of daytime ambulatory systolic blood pressure. Peripheral vascular dysfunction, however, remains unchanged and may contribute to residual hypertension.