Renal artery and parenchymal changes after renal denervation: assessment by magnetic resonance angiography.

OBJECTIVES: Relatively little is known about the incidence of long-term renal damage after renal denervation (RDN), a potential new treatment for hypertension. In this study the incidence of renal artery and parenchymal changes, assessed with contrast-enhanced magnetic resonance angiography (MRA) after RDN, is investigated. METHODS: This study is an initiative of ENCOReD, a collaboration of hypertension expert centres. Patients in whom an MRA was performed before and after RDN were included. Scans were evaluated by two independent, blinded radiologists. Primary outcome was the change in renal artery morphology and parenchyma. RESULTS: MRAs from 96 patients were analysed. Before RDN, 41 renal anomalies were observed, of which 29 mostly mild renal artery stenoses. After a median time of 366 days post RDN, MRA showed a new stenosis (25-49% lumen reduction) in two patients and progression of pre-existing lumen reduction in a single patient. No other renal changes were observed and renal function remained stable. CONCLUSIONS: We observed new or progressed renal artery stenosis in three out of 96 patients, after a median time of 12 months post RDN (3.1%). Procedural angiographies showed that ablations were applied near the observed stenosis in only one of the three patients. KEY POINTS: • The incidence of vascular changes 12 months post RDN was 3.1%. • No renal vascular or parenchymal changes other than stenoses were observed. • Ablations were applied near the stenosis in only one of three patients.

Assessment of left ventricular function in ST-elevation myocardial infarction by global longitudinal strain: a comparison with ejection fraction, infarct size, and wall motion score index measured by non-invasive imaging modalities.

AIMS: We aimed to compare two-dimensional global longitudinal strain (GS) with different non-invasive imaging modalities for the assessment of left ventricular function in an ST-elevation myocardial infarction population. METHODS AND RESULTS: GS was compared with ejection fraction (EF) determined by magnetic resonance imaging (MRI), standard echocardiography (echo), contrast echo, and electrocardiography-gated single-photon emission computed tomography (SPECT), as well as with MRI-determined relative infarct size and echo-determined wall motion score index (WMSI), in 163 patients participating in the NORwegian Study on District Treatment of ST-Elevation Myocardial Infarction (NORDISTEMI). The linear relation between GS and standard echo (r(2)= 0.43, P <0.001), contrast echo (r(2)= 0.38, P <0.001), and SPECT-determined EF (r(2)= 0.52, P <0.001) was almost identical as that between GS and the gold standard MRI-determined EF (r(2)= 0.47, P <0.001). GS was best associated with WMSI by echo (r(2)= 0.55, P <0.001), while the associations between GS and relative infarct size were weaker (r = 0.43, P <0.001). Receiver operator characteristics curves, used to analyse the ability of GS to discriminate low EF (≤ 40%) measured by the four different modalities, large myocardial infarction (MI ≥ 15.7%), and high WMSI (≥ 1.5), were significant for all. GS was shown to be the best predictor of low EF measured by MRI [area under the curve (AUC) 0.965], while the lowest AUC was found between GS and large MI (0.814). CONCLUSION: Global strain is associated well with EF measured by all modalities. Global strain was found to be the best predictor of low EF measured by the gold standard MRI. Since global strain is an inexpensive test, these data may be of health economic interest.

Assessment of left ventricular function with magnetic resonance imaging vs. echocardiography, contrast echocardiography, and single-photon emission computed tomography in patients with recent ST-elevation myocardial infarction.

AIMS: Magnetic resonance imaging (MRI) is often considered to be the gold standard in measuring left ventricular function and volumes. The aim of this study was to assess the agreements between standard echocardiography (standard echo), contrast echocardiography (contrast echo), single-photon emission computed tomography (SPECT), and MRI in the determination of left ventricular ejection fraction (EF) and end-diastolic volumes (EDV) in patients treated for acute ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: Standard echo, contrast echo, SPECT and MRI were performed on the same day, 3 months after STEMI in 150 patients participating in the NORwegian Study on District Treatment of ST-Elevation Myocardial Infarction (NORDISTEMI). Bland-Altman analysis of EF measured by all four imaging modalities showed generally low mean differences but wide limits of agreement. The mean EDV difference, however, was consistently higher when MRI was compared with standard echo (54.9 mL), contrast echo (41.7 mL) and SPECT (54.6 mL), and the limits of agreement were wider. The mean EDV differences between contrast echo vs. standard echo, SPECT vs. standard echo and contrast echo vs. SPECT were small. CONCLUSION: Our data suggest that all four imaging modalities measured EF closely similar after STEMI as demonstrated by a very small bias. The limits of agreement were however wide. EDV measured by MRI was consistently higher when compared with the other methods which may be caused by different tracing-methods and imaging principles. As echocardiography is preferable from a cost-benefit point of view, further analysis would be needed to clarify the nature of such differences.