Christopher D Steadman

Natriuretic Peptides in Common Valvular Heart Disease

Valvular heart disease, particularly aortic stenosis and mitral regurgitation, accounts for a large proportion of cardiology practice, and their prevalence is predicted to increase. Management of the asymptomatic patient remains controversial. Biomarkers have been shown to have utility in the management of cardiovascular disease such as heart failure and acute coronary syndromes. In this state-of-the-art review, we examine the current evidence relating to natriuretic peptides as potential biomarkers in aortic stenosis and mitral regurgitation. The natriuretic peptides correlate with measures of disease severity and symptomatic status and also can be used to predict outcome. This review shows that natriuretic peptides have much promise as biomarkers in common valvular heart disease, but the impact of their measurement on clinical practice and outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality.

Assessment of valve haemodynamics, reverse ventricular remodelling and myocardial fibrosis following transcatheter aortic valve implantation compared to surgical aortic valve replacement: a cardiovascular magnetic resonance study

Objective To compare the effects of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) on aortic valve haemodynamics, ventricular reverse remodelling and myocardial fibrosis (MF) by cardiovascular magnetic resonance (CMR) imaging. Design A 1.5 T CMR scan was performed preoperatively and 6 months postoperatively. Setting University hospitals of Leeds and Leicester, UK. Patients 50 (25 TAVI, 25 SAVR; age 77±8 years) high-risk severe symptomatic aortic stenosis (AS) patients. Main outcome measures Valve haemodynamics, ventricular volumes, ejection fraction (EF), mass and MF. Results Patients were matched for gender and AS severity but not for age (80±6 vs 73±7 years, p=0.001) or EuroSCORE (22±14 vs 7±3, p<0.001). Aortic valve mean pressure gradient decreased to a greater degree post-TAVI compared to SAVR (21±8 mm Hg vs 35±13 mm Hg, p=0.017). Aortic regurgitation reduced by 8% in both groups, only reaching statistical significance for TAVI (p=0.003). TAVI and SAVR improved (p<0.05) left ventricular (LV) end-systolic volumes (46±18 ml/m2 vs 41±17 ml/m2; 44±22 ml/m2 vs32±6 ml/m2) and mass (83±20 g/m2 vs 65±15 g/m2; 74±11 g/m2 vs 59±8 g/m2). SAVR reduced end-diastolic volumes (92±19 ml/m2 vs 74±12 ml/m2, p<0.001) and TAVI increased EF (52±12% vs 56±10%, p=0.01). MF reduced post-TAVI (10.9±6% vs 8.5±5%, p=0.03) but not post-SAVR (4.2±2% vs 4.1±2%, p=0.98). Myocardial scar (p≤0.01) and baseline ventricular volumes (p<0.001) were the major predictors of reverse remodelling. Conclusions TAVI was comparable to SAVR at LV reverse remodelling and superior at reducing the valvular pressure gradient and MF. Future work should assess the prognostic importance of reverse remodelling and fibrosis post-TAVI to aid patient selection.

Intertechnique agreement and interstudy reproducibility of strain and diastolic strain rate at 1.5 and 3 Tesla: a comparison of feature-tracking and tagging in patients with aortic stenosis.

To determine the interstudy reproducibility of myocardial strain and peak early‐diastolic strain rate (PEDSR) measurement on cardiovascular magnetic resonance imaging (MRI) assessed with feature tracking (FT) and tagging, in patients with aortic stenosis (AS).

Comparison of local sine wave modeling with harmonic phase analysis for the assessment of myocardial strain.

To compare local sine‐wave modeling (SinMod) with harmonic phase analysis (HARP), for assessment of left ventricular (LV) circumferential strain (εcc) from tagged cardiovascular magnetic resonance images.

Managing the asymptomatic patient with severe aortic stenosis: randomised controlled trials of early surgery are overdue

In the developed world, aortic stenosis (AS) is the commonest valve disease requiring surgery. AS is common in the elderly and up to 3% of subjects over 75 years of age may have severe disease.1 In the past decade the number of isolated aortic valve replacements (AVRs) performed in the USA and the UK has doubled. As the population in developed countries continues to age, it is predicted that the prevalence of AS will double in the next 20 years. Cardiologists and cardiac surgeons will increasingly face the dilemma of how to manage optimally this important group of predominantly elderly patients, many of whom will be asymptomatic and have been identified by the incidental finding of a systolic murmur or abnormal ECG. The development of symptoms in severe AS heralds a malignant phase of the condition and prompt AVR results in a clear reduction in mortality, which is still apparent in the modern era, reflecting the lack of effective medical treatments.2 Surgery in this situation is universally regarded as a class I indication despite the absence of randomised controlled trials (RCTs).3 4 In contrast, the management of patients with severe AS in the absence of symptoms remains one of the most controversial areas in modern cardiology, reflected in differences in guidelines of the major cardiovascular societies.3 4 Currently the European Society of Cardiology (ESC)3 regards symptoms on exercise testing as …

Stress cardiovascular MR in routine clinical practice: referral patterns, accuracy, tolerance, safety and incidental findings

OBJECTIVE The use of stress cardiovascular MR (CMR) to evaluate myocardial ischaemia has increased significantly over recent years. We aimed to assess the indications, incidental findings, tolerance, safety and accuracy of stress CMR in routine clinical practice. METHODS We retrospectively examined all stress CMR studies performed at our tertiary referral centre over a 20-month period. Patients were scanned at 1.5 T, using a standardised protocol with routine imaging for late gadolinium enhancement. Angiograms of patients were assessed by an interventional cardiologist blinded to the CMR data. RESULTS 654 patients were scanned (mean age 65±29 years; 63 inpatients; 9.6%). 14% of patients had incidental extracardiac findings, the commonest being liver or renal cysts (6%) and pulmonary nodules (4%). 639 patients (97.7%) received intravenous adenosine, 10 received intravenous dobutamine and 5 patients had both. Of the 15 patients who received dobutamine, 12 had no side-effects/complications, 2 experienced nausea and 1 chest tightness. Of the 644 patients who received adenosine, 43% experienced minor symptoms, 1% had transient heart block and 0.2% had severe bronchospasm requiring termination of infusion. There were no cases of hospitalisation or myocardial infarction. 241 patients also had coronary angiography. For detecting at least moderate stenosis of ≥50%, sensitivity was 86%, specificity 98% and accuracy 89%. For detecting severe stenoses of ≥70%, sensitivity was 91%, specificity 86% and overall accuracy 90%. These results compare very favourably with previous smaller research studies and meta-analyses. CONCLUSION We conclude that stress CMR, with adenosine as the main stress agent, is well tolerated, safe and accurate in routine clinical practice.

Dressler's syndrome demonstrated by late gadolinium enhancement cardiovascular magnetic resonance

A 49-year old patient presented late with an anterolateral ST-elevation myocardial infarction and was treated with rescue angioplasty to an occluded left anterior descending artery. Her recovery was complicated by low-grade pyrexia and raised inflammatory markers. Cardiovascular magnetic resonance 5 weeks after the acute presentation showed transmural infarction and global late gadolinium enhancement of the pericardium in keeping with Dresslers syndrome.

Difference between cerebral embolic events following Transcatheter Aortic Valve Implantation (TAVI) and Surgical Aortic Valve Replacement (SAVR): a diffusion weighted MRI study

Background Transcatheter Aortic Valve Implantation (TAVI) is used to treat symptomatic severe aortic stenosis in a non-surgical high risk population. The incidence of stroke and micro-infarction is higher in the TAVI population compared to surgical aortic valve replacement (SAVR) at 30 days, which may be due to various factors such as valve calcification and aortic atheroma. However, the natural history and clinical consequences of micro-infarction is unknown.

Right ventricular function following surgical aortic valve replacement and transcatheter aortic valve implantation: A cardiovascular MR study

OBJECTIVE The response of the RV following treatment of aortic stenosis is poorly defined, reflecting the challenge of accurate RV assessment. Cardiovascular magnetic resonance (CMR) is the established reference for imaging of RV volumes, mass and function. We sought to define the impact of transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) upon RV function in patients treated for severe aortic stenosis using CMR. METHODS A 1.5T CMR scan was performed preoperatively and 6months postoperatively in 112 (56 TAVI, 56 SAVR; 76±8years) high-risk severe symptomatic aortic stenosis patients across two UK cardiothoracic centres. RESULTS TAVI patients were older (80.4±6.7 vs. 72.8±7.2years, p<0.05) with a higher STS score (2.13±0.73 vs. 5.54±3.41%, p<0.001). At 6months, SAVR was associated with a significant increase in RV end systolic volume (33±10 vs. 37±10ml/m2, p=0.008), and decrease in RV ejection fraction (58±8 vs. 53±8%, p=0.005) and tricuspid annular plane systolic excursion (22±5 vs. 14±3mm, p<0.001). Only 4 (7%) SAVR patients had new RV late gadolinium hyper-enhancement with no new cases seen in the TAVI patients at 6months. Longer surgical cross-clamp time was the only predictor of increased RV end systolic volume at 6months. Post-TAVI, there was no observed change in RV volumes or function. Over a maximum 6.3year follow-up, 18(32%) of TAVI patients and 1(1.7%) of SAVR patients had died (p=0.001). On multivariable Cox analysis, the RV mass at 6m post-TAVI was independently associated with all-cause mortality (HR 1.359, 95% CI 1.108-1.666, p=0.003). CONCLUSIONS SAVR results in a deterioration in RV systolic volumes and function associated with longer cross-clamp times and is not fully explained by suboptimal RV protection during cardiopulmonary bypass. TAVI had no adverse impact upon RV volumes or function.

Inter-study reproducibility of circumferential strain and strain rates at 1.5T and 3T: a comparison of tagging and feature tracking

Background Feature Tracking (FT) is a relatively new technique for measuring strain on cardiac magnetic resonance imaging (CMR), that has been shown to have reasonable interstudy reproducibility (Coefficient of variation (CoV) ~20%) in healthy volunteers. The inter-study reproducibility of FT has not yet been reported in any patient groups, nor compared to that of MRI tagging. We sought to determine the inter-study reproducibility of circumferential strain and strain rates using FT and tagging at 1.5T and 3T scanners, in patients with moderate-severe Aortic Stenosis (AS). Methods CMR was performed twice in 8 patients with severe AS on a 1.5T scanner and 10 patients with moderate-severe AS at 3T. Three short-axis tagged images were acquired, in addition to the standard SSFP short-axis cine stack. InTag (Creatis, Lyon, France) in OsiriX (Geneva, Switzerland) was used to calculate the Circumferential Peak Systolic Strain (PSS), Peak Systolic Strain Rate (PSSR) and Peak Early Diastolic Strain Rate (PEDSR). Diogenes CMR FT (TomTec Imaging Systems, Munich, Germany) was used to calculate the same parameters on nearest SSFP cine images. Results Overall, FT gave higher strain and strain rate values when compared to tagging. On paired sample t-tests, there was no significant difference in the strain and strain rate values between scan one and scan two, using both tagging and FT, at both 1.5T and 3T. The inter-study reproducibility of both techniques was higher at 1.5T compared to 3T. (Table 1, Figure 1) Comparing tagging vs FT, PSS was more reproducible with FT at both 1.5T and 3T, while PSSR was more reproducible with tagging. PEDSR demonstrated similar inter-study reproducibility using both techniques, but was much more reproducible at 1.5T than 3T. (CoV’s for circumferential PSS, PSSR and PEDSR at 1.5T- FT: 8.6, 11.8 and 13.1%, tagging: 12.2, 9.4 and 17.5%; CoV’s at 3T-FT: 9.4, 23 and 25.6%, tagging: 17.9, 19.3 and 32.5%). Conclusions Both tagging and FT have good reproducibility at 1.5T and modest reproducibility at 3T scanners. This may partly be due to greater artefacts at 3T. Overall, FT appears to have higher reproducibility than tagging for circumferential PSS, while PSSR is more reproducible with tagging. If the main parameter of interest is PEDSR, scanning at 1.5T and using FT is more preferable. Given that FT does not require additional image acquisitions and involves shorter post-processing time, this technique is likely to become the preferred method for strain and strain rate quantification with CMR.