Isabelle Roussin

Midwall fibrosis is an independent predictor of mortality in patients with aortic stenosis.

OBJECTIVESnThe goal of this study was to assess the prognostic significance of midwall and infarct patterns of late gadolinium enhancement (LGE) in aortic stenosis.nnnBACKGROUNDnMyocardial fibrosis occurs in aortic stenosis as part of the hypertrophic response. It can be detected by LGE, which is associated with an adverse prognosis in a range of other cardiac conditions.nnnMETHODSnBetween January 2003 and October 2008, consecutive patients with moderate or severe aortic stenosis undergoing cardiovascular magnetic resonance with administration of gadolinium contrast were enrolled into a registry. Patients were categorized into absent, midwall, or infarct patterns of LGE by blinded independent observers. Patient follow-up was completed using patient questionnaires, source record data, and the National Strategic Tracing Service.nnnRESULTSnA total of 143 patients (age 68 ± 14 years; 97 male) were followed up for 2.0 ± 1.4 years. Seventy-two underwent aortic valve replacement, and 27 died (24 cardiac, 3 sudden cardiac deaths). Compared with those with no LGE (n = 49), univariate analysis revealed that patients with midwall fibrosis (n = 54) had an 8-fold increase in all-cause mortality despite similar aortic stenosis severity and coronary artery disease burden. Patients with an infarct pattern (n = 40) had a 6-fold increase. Midwall fibrosis (hazard ratio: 5.35; 95% confidence interval: 1.16 to 24.56; p = 0.03) and ejection fraction (hazard ratio: 0.96; 95% confidence interval: 0.94 to 0.99; p = 0.01) were independent predictors of all-cause mortality by multivariate analysis.nnnCONCLUSIONSnMidwall fibrosis was an independent predictor of mortality in patients with moderate and severe aortic stenosis. It has incremental prognostic value to ejection fraction and may provide a useful method of risk stratification.

Multimodality Imaging in Transcatheter Aortic Valve Implantation and Post-Procedural Aortic Regurgitation : Comparison Among Cardiovascular Magnetic Resonance, Cardiac Computed Tomography, and Echocardiography

OBJECTIVESnThe purpose of this study was to determine imaging predictors of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) and the agreement and reproducibility of cardiovascular magnetic resonance (CMR), cardiac computed tomography (CCT), and transthoracic echocardiography (TTE) in aortic root assessment.nnnBACKGROUNDnThe optimal imaging strategy for planning TAVI is unclear with a paucity of comparative multimodality imaging data. The association between aortic root morphology and outcomes after TAVI also remains incompletely understood.nnnMETHODSnA total of 202 consecutive patients assessed by CMR, CCT, and TTE for TAVI were studied. Agreement and variability among and within imaging modalities was assessed by Bland-Altman analysis. Postoperative AR was assessed by TTE.nnnRESULTSnOf the 202 patients undergoing TAVI assessment with both CMR and TTE, 133 also underwent CCT. Close agreement was observed between CMR and CCT in dimensions of the aortic annulus (bias, -0.4 mm; 95% limits of agreement: -5.7 to 5.0 mm), and similarly for sinus of Valsalva, sinotubular junction, and ascending aortic measures. Agreement between TTE-derived measures and either CMR or CCT was less precise. Intraobserver and interobserver variability were lowest with CMR. The presence and severity of AR after TAVI were associated with larger aortic valve annulus measurements by both CMR (p = 0.03) and CCT (p = 0.04) but not TTE-derived measures (p = 0.10). Neither CCT nor CMR measures of annulus eccentricity, however, predicted AR after TAVI (p = 0.33 and p = 0.78, respectively).nnnCONCLUSIONSnIn patients undergoing imaging assessment for TAVI, the presence and severity of AR after TAVI were associated with larger aortic annulus measurements by both CMR and CCT, but not TTE. Both CMR and CCT provide highly reproducible information in the assessment of patients undergoing TAVI.

Coronary artery bypass surgery with or without mitral valve annuloplasty in moderate functional ischemic mitral regurgitation: final results of the Randomized Ischemic Mitral Evaluation (RIME) trial.

Background—The role of mitral valve repair (MVR) during coronary artery bypass grafting (CABG) in patients with moderate ischemic mitral regurgitation (MR) is uncertain. We conducted a randomized, controlled trial to determine whether repairing the mitral valve during CABG may improve functional capacity and left ventricular reverse remodeling compared with CABG alone. Methods and Results—Seventy-three patients referred for CABG with moderate ischemic MR and an ejection fraction >30% were randomized to receive CABG plus MVR (34 patients) or CABG only (39 patients). The study was stopped early after review of interim data. At 1 year, there was a greater improvement in the primary end point of peak oxygen consumption in the CABG plus MVR group compared with the CABG group (3.3 mL/kg/min versus 0.8 mL/kg/min; P<0.001). There was also a greater improvement in the secondary end points in the CABG plus MVR group compared with the CABG group: left ventricular end-systolic volume index, MR volume, and plasma B-type natriuretic peptide reduction of 22.2 mL/m2, 28.2 mL/beat, and 557.4 pg/mL, respectively versus 4.4 mL/m2 (P=0.002), 9.2 mL/beat (P=0.001), and 394.7 pg/mL (P=0.003), respectively. Operation duration, blood transfusion, intubation duration, and hospital stay duration were greater in the CABG plus MVR group. Deaths at 30 days and 1 year were similar in both groups: 3% and 9%, respectively in the CABG plus MVR group, versus 3% (P=1.00) and 5% (P=0.66), respectively in the CABG group. Conclusions—Adding mitral annuloplasty to CABG in patients with moderate ischemic MR may improve functional capacity, left ventricular reverse remodeling, MR severity, and B-type natriuretic peptide levels, compared with CABG alone. The impact of these benefits on longer term clinical outcomes remains to be defined. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00413998.

Left ventricular remodeling and hypertrophy in patients with aortic stenosis: insights from cardiovascular magnetic resonance

BackgroundCardiovascular magnetic resonance (CMR) is the gold standard non-invasive method for determining left ventricular (LV) mass and volume but has not been used previously to characterise the LV remodeling response in aortic stenosis. We sought to investigate the degree and patterns of hypertrophy in aortic stenosis using CMR.MethodsPatients with moderate or severe aortic stenosis, normal coronary arteries and no other significant valve lesions or cardiomyopathy were scanned by CMR with valve severity assessed by planimetry and velocity mapping. The extent and patterns of hypertrophy were investigated using measurements of the LV mass index, indexed LV volumes and the LV mass/volume ratio. Asymmetric forms of remodeling and hypertrophy were defined by a regional wall thickening ≥ 13 mm and >1.5-fold the thickness of the opposing myocardial segment.ResultsNinety-one patients (61±21 years; 57 male) with aortic stenosis (aortic valve area 0.93±0.32cm2) were recruited. The severity of aortic stenosis was unrelated to the degree (r2=0.012, P=0.43) and pattern (P=0.22) of hypertrophy. By univariate analysis, only male sex demonstrated an association with LV mass index (P=0.02). Six patterns of LV adaption were observed: normal ventricular geometry (n=11), concentric remodeling (n=11), asymmetric remodeling (n=11), concentric hypertrophy (n=34), asymmetric hypertrophy (n=14) and LV decompensation (n=10). Asymmetric patterns displayed considerable overlap in appearances (wall thickness 17±2mm) with hypertrophic cardiomyopathy.ConclusionsWe have demonstrated that in patients with moderate and severe aortic stenosis, the pattern of LV adaption and degree of hypertrophy do not closely correlate with the severity of valve narrowing and that asymmetric patterns of wall thickening are common.Trial registrationClinicalTrials.gov Reference Number: NCT00930735

Prognostic role of CMR in patients presenting with ventricular arrhythmias.

OBJECTIVESnThe goal of this study was to explore whether fibrosis detected by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is an independent predictor of hard cardiovascular events in patients presenting with ventricular arrhythmia.nnnBACKGROUNDnIn patients at risk of sudden cardiac death, risk stratification for device therapy remains challenging.nnnMETHODSnA total of 373 consecutive patients with sustained ventricular tachycardia (VT) (n = 204) or nonsustained ventricular tachycardia (NSVT) (n = 169) underwent LGE-CMR. The group was prospectively followed up for a median of 2.6 years (range 11 months to 11 years). The predetermined endpoint was a composite of cardiac death/arrest, new episode of sustained VT, or appropriate implantable cardioverter-defibrillator discharge.nnnRESULTSnMean left ventricular (LV) ejection fraction (EF) was 60 ± 13%. The presence of fibrosis was a strong and independent predictor of the primary outcome for the whole group (hazard ratio [HR]: 3.3, 95% confidence interval [CI]: 1.8 to 5.8, p < 0.001). In the sustained VT subset, both LV fibrosis and severely impaired systolic function (LVEF <35%) were significant independent predictors in the multivariate model (HR: 3.0, 95% CI: 1.4 to 6.2, p = 0.001; and HR: 2.5, 95% CI: 1.1 to 6.2, p = 0.038, respectively). In the NSVT subset, the presence of fibrosis was the only independent predictor of the endpoint (HR: 4.2, 95% CI: 1.7 to 10.1, p = 0.006).nnnCONCLUSIONSnLGE-CMR-detected fibrosis is an independent predictor of adverse outcomes in patients with ventricular arrhythmia and may have an important role in risk stratification. (The Prognostic Significance of Fibrosis Detection in Ischemic and Non-Ischemic Cardiomyopathy; NCT00930735).

Prognostic value of cardiovascular magnetic resonance in patients with suspected arrhythmogenic right ventricular cardiomyopathy

BACKGROUNDnEarly recognition and accurate risk stratification are important in the management of arrhythmogenic right ventricular cardiomyopathy (ARVC). Identification of predictors of outcome by cardiovascular magnetic resonance (CMR) in patients undergoing evaluation for ARVC is limited. We investigated the predictive value of morphological abnormalities detected by CMR for major clinical events in patients with suspected ARVC.nnnMETHODSnWe performed a longitudinal study on 369 consecutive patients with at least one criterion for ARVC. Abnormal CMR was defined by the presence of one of the following: increased right ventricular (RV) volumes, reduced RV ejection fraction, RV regional wall motion abnormalities, myocardial fatty infiltration, and myocardial fibrosis. The end-point was a composite of cardiac death, sustained ventricular tachycardia, ventricular fibrillation, and appropriate ICD discharge.nnnRESULTSnTwenty patients met the composite end-point over a mean follow-up of 4.3±1.5 years. An abnormal CMR was an independent predictor of outcomes (p<0.001). The presence of multiple abnormalities heralded a particular high risk of events (HR 23.0, 95% CI 5.7-93.2, p<0.001 for 2 abnormalities; HR 35.8, 95% CI 9.7-132.6, p<0.001 for 3 or more abnormalities). The positive predictive value of an abnormal CMR study was 21.0% for an adverse event, whilst the negative predictive value of a normal CMR study was 98.8% over the follow-up period.nnnCONCLUSIONSnCMR provides important prognostic information in patients under evaluation for ARVC. A normal study portends a good prognosis. Conversely, the presence of multiple abnormalities identifies a high risk group of patients who may benefit from ICD implantation.

The Feasibility and Clinical Utility of Myocardial Contrast Echocardiography in Clinical Practice: Results from the Incorporation of Myocardial Perfusion Assessment into Clinical Testing with Stress Echocardiography Study

BACKGROUNDnThis prospective study investigated whether the incorporation of myocardial contrast echocardiography (MCE) into a clinical stress echocardiography service reproduces the benefits of assessing myocardial perfusion proved previously in research studies.nnnMETHODSnMCE was performed during physiologic and pharmacologic clinical stress echocardiographic studies, and the value of myocardial perfusion to the reporting echocardiologists was categorized as of benefit (subclassified as incremental benefit over wall motion [WM] or greater confidence with WM) or of no added benefit. The presence and extent of inducible ischemia by WM and myocardial perfusion were documented and correlated with angiographic results in patients who underwent cardiac catheterization.nnnRESULTSnIn total, 220 patients underwent simultaneous MCE during stress echocardiography by eight different operators. Overall, MCE was of benefit in 193 patients (88%), providing incremental benefit over WM in 25% and greater confidence with WM evaluation in 62%. MCE provided no added benefit in 27 patients (12%). MCE detected significantly more cases of ischemia than WM in the left anterior descending coronary artery territory (65% vs 53%, P = .02) and detected a greater ischemic burden than WM on a per patient basis (median, 5 [interquartile range, 3-8] vs 4 [interquartile range, 2-7] segments; P < .001) and across all coronary territories. MCE correctly identified a greater proportion of patients with multivessel disease than WM (76% vs 56%, P = .02) and a greater ischemic burden in patients with multivessel disease (median, 7 [interquartile range, 4-9] vs 5 [interquartile range, 1-8] segments; P < .001).nnnCONCLUSIONSnThis prospective study is the first to demonstrate that the excellent feasibility and diagnostic utility of MCE, which have been documented in the research arena, are reproducible in the clinical arena.

Clinical and prognostic value of stress echocardiography appropriateness criteria for evaluation of coronary artery disease in a tertiary referral centre

Objective Appropriateness criteria for stress echocardiography (SE) have been published to reduce the rate of inappropriate testing. We sought to investigate the clinical impact and prognostic value of these criteria. Methods 250 consecutive patients undergoing SE for evaluation of coronary artery disease were classified into appropriate, uncertain and inappropriate categories according to appropriateness criteria. A positive SE was defined as the development of new wall motion abnormalities or a biphasic response. The primary end point was the composite of myocardial infarction and death. Results Of the 250 SE, 120 (48%) were dobutamine studies and 130 (52%) were exercise studies. 156 (62.4%), 71 (28.4%) and 23 (9.2%) were classified as appropriate, inappropriate and uncertain, respectively. A significantly greater proportion of studies classified as appropriate 71 (45.5%) demonstrated inducible ischaemia compared with inappropriate studies 9 (12.7%) or uncertain studies 4 (17.4%), p<0.0001. During a median follow-up of 12.4u2005months, events occurred in 18 (11.5%), 2 (2.8%) and 0 patients classified as appropriate, inappropriate and uncertain, respectively. Event-free survival was significantly reduced in patients with a SE demonstrating ischaemia compared with patients without inducible ischaemia, p<0.0001. Kaplan–Meier curves demonstrated reduced event-free survival in patients with whose studies were classified as appropriate compared to inappropriate (p=0.01) or uncertain (p=0.05). Conclusions Appropriateness criteria differentiate between patients at high risk of ischaemia, subsequent revascularisation/cardiac events (appropriate group) and those at low risk of events (inappropriate group). A large proportion of SE is currently performed in inappropriate patients. Implementation of the criteria in clinical practice would reduce unnecessary testing.

Clinical Utility and Prognostic Value of Appropriateness Criteria in Stress Echocardiography for the Evaluation of Valvular Heart Disease

We examined the prognostic value of stress echocardiography appropriateness criteria for evaluation of valvular heart disease in 100 consecutive patients. Of the studies, 49%, 36%, and 15% were classified as appropriate, uncertain, and inappropriate, respectively. Over a median of 12.6 months, 24 events (12 deaths and 12 heart failure admissions) occurred. The 12-month event-free survival was significantly reduced in patients with appropriate or uncertain studies compared with patients with inappropriate studies (p = 0.04 and p = 0.005, respectively). There was no survival difference between patients with an appropriate or uncertain indication (p = 0.1). The only independent predictors of events were a positive stress echocardiogram (hazard ratio: 15.5, p < 0.0001) and left ventricular ejection fraction (hazard ratio: 0.95, p = 0.02). The appropriateness criteria for evaluation of valvular heart disease provide the ability to differentiate between patients at high- (appropriate group) and low- (inappropriate group) risk of cardiac events. Reclassification of the uncertain group may improve the differential value of these criteria.

Failing stentless aortic valves: redo aortic root replacement or valve in a valve?

OBJECTIVESnReoperation for failing stentless aortic valve replacement is a technically demanding procedure that has traditionally been tackled in one of two ways: either root replacement or the more conservative option of implanting a stented valve within the valve. We sought to determine the relative operative risks, follow-up status and medium to long-term survival of these two methods.nnnMETHODSnWe conducted a retrospective review of a single surgeons experience of the two techniques over a 10-year period from 2000 to 2010. Excluding cases of active endocarditis, 110 patients were identified, of which 65 underwent valve-in-valve procedures (Group A) and 45 had redo root replacement (Group B). The most common bioprostheses reoperated were homografts (roots or subcoronary implants) and Toronto Stentless Porcine Valves. Aortic valve replacement alone was performed in 68% in Group A and 64% in Group B, with males comprising 75% of Group A and 82% of Group B. Average ages were 61.5 ± 14.2 years and 61.9 ± 12.1 years, respectively.nnnRESULTSnOperative and cardiopulmonary bypass durations were significantly greater for redo root procedures and correspondingly, postoperative complications were more common. Thirty-day mortality after valve-in-valve replacement was 3%, and after redo root replacement it was 11%. Despite significantly higher transvalvular gradients in Group B, the symptomatic status was equally good at 2 months, 1 year and last follow-up. At an average interval of 5.1 ± 2.7 years for Group A, survival was 83% vs 76% at 7.3 ± 2.9 years for Group B. There have been two reinterventions in Group A and 3 in Group B. Only one valve-in-valve patient has developed a paraprosthetic leak.nnnCONCLUSIONSnThis retrospective review has confirmed our hypothesis that where both root diameter permits and satisfactory debridement can be performed, valve-in-valve replacement is the more conservative surgical strategy for stentless aortic valve replacement revision. Although transvalvular gradients on echocardiography are significantly higher with the introduction of a stented prosthesis, medium-term outcomes in terms of symptomatic status, late complications and reintervention rate were non-inferior. We await the medium-term results of transcatheter aortic valve implantation for the same indication with interest.