INTRODUCTION: Patients with paradoxical low-flow (LF) severe aortic stenosis (AS) despite preserved left ventricular ejection fraction (LVEF) appear distinct from normal-flow (NF) patients, showing worse prognosis, more concentric hypertrophy and smaller left ventricular (LV) cavities. The left ventricular remodelling index (LVRI) has been demonstrated to reliably discriminate between physiologically adapted athlete's heart and pathological LV remodelling. METHODS: We studied patients with index echocardiographic diagnosis of severe AS (aortic valve area <1 cm2) with preserved LVEF (>50%). The LVRI was determined by the ratio of the LV mass to the end-diastolic volume, as previously reported, and was compared between patients with LF and NF AS. Patients were prospectively followed up for at least 3 years, and clinical outcomes were examined in association with LVRI. RESULTS: Of the 450 patients studied, 112 (24.9%) had LF AS. While there were no significant differences in baseline clinical profile between LF and NF patients, LVRI was significantly higher in the LF group. Patients with high LVRI (>1.56 g/mL) had increased all-cause mortality (log-rank 9.18, P = 0.002) and were more likely to be admitted for cardiac failure (log-rank 7.61, P = 0.006) or undergo aortic valve replacement (log-rank 18.4, P < 0.001). After adjusting for the effect of age, hypertension, aortic valve area and mean pressure gradient on multivariate Cox regression, high LVRI remained independently associated with poor clinical outcomes (hazard ratio 1.64, 95% confidence interval 1.19-2.25, P = 0.002). CONCLUSION: Pathological LV remodelling (increased LVRI) was more common in patients with LF AS, and increased LVRI independently predicts worse clinical outcomes.
Vortex formation during left ventricular diastolic filling may provide clinically useful insights into cardiac health. In recent years, there has been growing interest in the measurement of vortex formation time (VFT), especially because it is derived noninvasively. There are important applications of VFT in valvular heart disease, athletic physiology, heart failure and hypertrophic cardiomyopathy. The formation of the vortex as fluid propagates into the left ventricle from the left atrium is important for efficient fluid transport. Quantifying VFT may thus help in evaluating and understanding disease and pathophysiological processes.
BACKGROUND: Paradoxical low-flow (LF) severe aortic stenosis (AS) despite preserved left ventricular (LV) ejection fraction (LVEF) has been shown to be distinct from normal-flow (NF) AS, with a poorer prognosis. Relative valve load (RVL) is a novel echocardiographic haemodynamic index based on the ratio of transaortic mean pressure gradient to the global valvulo-arterial impedance (Zva) in order to estimate the contribution of the valvular afterload to the global LV load. We aimed to determine the usefulness of RVL in LF AS versus NF AS. METHOD: A total of 450 consecutive patients with medically managed severe AS (aortic valve area <1.0 cm2) with preserved LVEF (>50%) were studied. Patients were divided into LF (stroke volume index <35 mL/m2) or NF, and high RVL or low RVL. Baseline clinical and echocardiographic profiles, as well as clinical outcomes, were compared. RESULTS: There were 149 (33.1%) patients with LF. Despite higher global impedance in LF (Zva 6.3±2.4 vs 3.9±0.9 mmHg/mL/m2; p<0.001) compared with NF, the RVL in LF AS was significantly lower (5.4±2.7 vs 9.8±5.1 mL/m2; p<0.001). On multivariable analysis, low RVL (≤7.51) remained independently associated with poor clinical outcomes on Cox regression (hazard ratio, 1.31; 95% confidence interval, 1.03-1.68), with 53.2% sensitivity and 70.3% specificity. This was comparable to other prognostic indices in AS. Kaplan-Meier curves demonstrated that low RVL was associated with increased mortality. CONCLUSIONS: Increased systemic arterial afterload may be important in the pathophysiology of LF AS. Low RVL was an independent predictor of poor clinical outcomes in medically managed severe AS. There may be a greater role in the attenuation of systemic arterial afterload in AS to improve outcomes.
Aortic Valve Stenosis , Ventricular Function, Left , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aortic Valve Stenosis/diagnosis , Aortic Valve Stenosis/surgery , Humans , Retrospective Studies , Severity of Illness Index , Stroke Volume
Cefazolin is a widely used first-generation cephalosporin. While generally well tolerated, several case reports have described severe coagulopathy induced by intravenous (IV) cefazolin. This was seen particularly in patients with impaired renal function, where antibiotic choice is limited and may require specific dose adjustments. Altered renal handling of antibiotics and their metabolites may potentiate toxicity and side effects. We report a case of a 72-year-old Chinese man who had been treated for methicillin-sensitive staphylococcus aureus (MSSA, coagulase-positive) infective endocarditis with cefazolin and, consequently, developed significantly elevated international normalised ratio (INR) while on therapy. This resolved within 48 h after cessation of cefazolin and administration of oral vitamin K. Malnourished patients with pre-existing or acute kidney injury may be at an increased risk of cefazolin-related coagulopathy.
Left ventricular vortex formation time (VFT) is a novel dimensionless index of flow propagation during left ventricular diastole, which has been demonstrated to be useful in heart failure and cardiomyopathy. In mitral stenosis (MS), flow propagation in the LV may be suboptimal. We studied VFT in varying degrees of MS. Echocardiography was performed on 20 healthy controls and 50 cases of rheumatic MS. Patients with atrial fibrillation, LV ejection fraction < 50% and other valvular heart diseases were excluded. VFT was obtained using the length-to-diameter ratio (L/D), where L is the continuous-wave Doppler velocity time integral stroke distance, divided by D, the mitral leaflet separation index. This was correlated against varying degrees of MS severity, left atrial (LA) volume and function. In controls, VFT was 3.92 ± 2.00 (optimal range) and was higher (suboptimal) with increasing severity of mitral stenosis (4.98 ± 2.43 in mild MS; 7.22 ± 2.98 in moderate MS; 11.55 ± 2.67 in severe MS, p < 0.001). VFT negatively correlated with mitral valve area (R2 = 0.463, p < 0.001) and total LA emptying fraction (R2 = 0.348, p < 0.001), and positively correlated with LA volume index (R2 = 0.440, p < 0.001) and mean transmitral pressure gradient (R2 = 0.336, p < 0.001). More severe MS correlated with suboptimal (higher) VFT. The restricted mitral valve opening may disrupt vortex formation and optimal fluid propagation in the LV. Despite the compensatory increase in LA size with increasingly severe MS, reduced LA function also contributed to the suboptimal LV vortex formation.
Mitral Valve Stenosis , Diastole , Heart Ventricles , Humans , Mitral Valve/diagnostic imaging , Mitral Valve Stenosis/diagnostic imaging , Predictive Value of Tests
Background: Aortic regurgitation (AR) is a common comorbidity in patients with aortic stenosis (AS), but coexisting AR has often been excluded from major clinical studies on AS. The impact of coexisting AR on the natural history of AS has not been well-described. Objectives: The authors compared clinical outcomes in medically managed patients with moderate-to-severe AS with or without coexisting AR. Methods: Consecutive patients (N = 1,188) with index echocardiographic diagnosis of moderate-to-severe AS (aortic valve area <1.5 cm2) were studied. All patients were medically managed and were divided into those with coexisting AR (at least moderate severity) and those without. Adverse composite clinical outcomes were defined as mortality or admissions for congestive cardiac failure on subsequent follow-up. The authors compared differences in clinical profile and outcomes between the groups. Results: There were 88 patients (7.4%) with coexisting AR and AS. These patients did not differ significantly in age, but had lower body mass index (22.9 ± 3.8 vs 25.3 ± 5.1 kg/m2), lower diastolic blood pressure (68.7 ± 10.7 vs 72.2 ± 12.3 mm Hg), larger end-diastolic volume index (68.8 ± 18.8 vs 60.4 ± 17.8 mL/m2) and larger left ventricular mass index (118.6 ± 36.4 vs 108.9 ± 33.1 g/m2). The prevalence of cardiovascular risk factors did not differ significantly. Coexisting AR was associated with increased incidence of adverse outcomes (log-rank 4.20; P = 0.040). On multivariable Cox regression, coexisting AR remained independently associated with adverse outcomes (HR: 1.36; 95% CI: 1.02-1.82) after adjusting for age, AS severity, left ventricular ejection fraction, and year of study. Conclusions: In patients with AS, coexisting AR was associated with changes in echocardiographic profile and adverse outcomes.
