Underestimation of Aortic Stenosis Severity by Doppler Mean Gradient during Atrial Fibrillation: Insights from Aortic Valve Weight

BACKGROUND

Doppler mean gradient (MG) can underestimate aortic stenosis (AS) severity when obtained during atrial fibrillation (AF) compared with sinus rhythm (SR). Aortic valve weight (AVW) is a flow-independent measure of AS severity. The objective of this study was to determine whether AVW or AVW/MG ratio was increased in AF versus SR in patients with AS.

METHODS

Excised native aortic valves from 495 consecutive patients (median age, 77 years; interquartile range [IQR], 71-82 years; 40% women), with left ventricular ejection fractions ≥50% who underwent surgical aortic valve replacement for native valve severe AS (aortic valve area ≤ 1 cm² or indexed aortic valve area ≤ 0.6 cm²/m²) were weighed. Excised AVW/MG ratios were compared in AF versus SR in patients with high-gradient AS (aortic peak velocity ≥ 4 m/sec or MG ≥ 40 mm Hg) and low-gradient AS (aortic peak velocity < 4 m/sec and MG < 40 mm Hg) in sex-specific analyses.

RESULTS

AF was present in 51 patients (10%; 11 of 51 [22%] had low-gradient AS) and SR in 444 (90%; 23 of 444 [5%] had low-gradient AS). There was no difference in sex distribution between AF and SR. Aortic valve area was not different, but forward stroke volume index and transaortic valve flow rate were lower in AF (P ≤ .002 for all); MG was lower in AF versus SR (median, 46 mm Hg [IQR, 37-50 mm Hg] vs 50 mm Hg [IQR, 44-61 mm Hg]; P < .0001). Overall AVW was not different (median, 2,290 mg [IQR, 1,830-3,063 mg] vs 2,140 mg [IQR, 1,530-2,958 mg]; P = .31), but overall AVW/MG ratio was higher in AF (median, 55 [IQR, 41-67] vs 42 [IQR, 30-55]; P = .001). In sex- and MG-specific analyses, the AVW/MG ratio was higher in AF compared with SR in men with high-gradient AS (median, 58 [IQR, 41-75] vs 51 [IQR, 39-61]; P = .03), but the differences were not statistically significant between AF and SR in other groups.

CONCLUSIONS

AVW was discordant to Doppler MG in AF compared with SR in men with high-gradient AS. Additional studies of the relationship of MG to other measures of AS severity, such as leaflet fibrosis, are needed.

Left atrial appendage morphology predicts the formation of left atrial appendage thrombus

BACKGROUND

Nonchicken wing left atrial appendage (LAA) morphology is associated with higher risk for stroke in patients with atrial fibrillation (AF) than chicken wing (CW) morphology.

OBJECTIVE

Assess whether LAA morphology predicts the formation of LAA thrombus independent of age, sex, presenting rhythm, left ventricular ejection fraction (LVEF), or anticoagulant use.

METHODS

A cross-sectional analysis was performed on patients prospectively enrolled in the Vanderbilt LAA Registry or presenting for transesophageal echocardiogram (TEE) between January 1, 2015, and November 1, 2017 (n = 306). Two physicians independently reviewed TEEs interpreted as having LAA thrombus. Determination of LAA morphology, ejection velocity, and presence of thrombus (n = 102) were based on 0°, 45°, 90°, and 135° TEE views. The control cohort (n = 204) included consecutive AF patients undergoing TEE without LAA thrombus.

RESULTS

LAA morphology in patients with LAA thrombus was: 35% windsock, 47% broccoli, and 12% CW. Windsock (odds ratio [OR], 4.0; 95% confidence interval [CI]: 1.7-9.3, p = .001) and broccoli (OR, 6.6; 95% CI: 2.6-16.6; p < .001) morphology were higher risk for thrombus compared to CW. Female sex predicted higher-odds for LAA thrombus (OR, 2.6; 95% CI: 1.4-4.8; p = .002) as did LAA-EV < 20 cm/s (OR, 11.12; 95% CI: 5.6-22.1). Anticoagulation use (OR, 0.5; 95% CI: 0.3-0.9; p = .03) and higher LVEF (OR, 0.95; 95% CI: 0.93-0.98; p < .001) were associated with lower risk. In patients with a CW morphology who had LAA thrombus, 4 of the 7 had an LAA-EV < 20 cm/s and acute systolic heart failure with LVEF < 30% or active malignancy. In multivariable linear regression analysis controlling for presenting rhythm, anticoagulant use, age, sex, and LVEF, CW morphology appears relatively protective from LAA thrombus (p = .001).

CONCLUSION

CW LAA morphology appears relatively protective against the formation of LAA thrombus.

Echocardiography Criteria for Structural Heart Disease in Patients With End-Stage Renal Disease Initiating Hemodialysis

BACKGROUND

Cardiovascular disease among hemodialysis (HD) patients is linked to poor outcomes. The Acute Dialysis Quality Initiative Workgroup proposed echocardiographic (ECHO) criteria for structural heart disease (SHD) in dialysis patients. The association of SHD with important patient outcomes is not well defined.

OBJECTIVES

This study sought to determine prevalence of ECHO-determined SHD and its association with survival among incident HD patients.

METHODS

We analyzed patients who began chronic HD from 2001 to 2013 who underwent ECHO ≤1 month prior to or ≤3 months following initiation of HD (n = 654).

RESULTS

Mean patient age was 66 ± 16 years, and 60% of patients were male. ECHO findings that met 1 or more and ≥3 of the new criteria were discovered in 87% and 54% of patients, respectively. Over a median of 2.4 years, 415 patients died: 108 (26%) died within 6 months. Five-year mortality was 62%. Age- and sex-adjusted structural heart disease variables associated with death were left ventricular ejection fraction (LVEF) ≤45% (hazard ratio [HR]: 1.48; confidence interval [CI]: 1.20 to 1.83) and right ventricular (RV) systolic dysfunction (HR: 1.68; CI: 1.35 to 2.07). An additive of higher death risk included LVEF ≤45% and RV systolic dysfunction rather than neither (HR: 2.04; CI: 1.57 to 2.67; p = 0.53 for test for interaction). Following adjustment for age, sex, race, diabetic kidney disease, and dialysis access, RV dysfunction was independently associated with death (HR: 1.66; CI 1.34 to 2.06; p < 0.001).

CONCLUSIONS

SHD was common in our HD study population, and RV systolic dysfunction independently predicted mortality.

Spontaneous coronary artery dissection and its association with heritable connective tissue disorders

OBJECTIVE

Spontaneous coronary artery dissection (SCAD) is an under-recognised but important cause of myocardial infarction and sudden cardiac death. We sought to determine the role of medical and molecular genetic screening for connective tissue disorders in patients with SCAD.

METHODS

We performed a single-centre retrospective descriptive analysis of patients with spontaneous coronary artery disease who had undergone medical genetics evaluation 1984-2014 (n=116). The presence or absence of traits suggestive of heritable connective tissue disease was extracted. Genetic testing for connective tissue disorders and/or aortopathies, if performed, is also reported.

RESULTS

Of the 116 patients (mean age 44.2 years, 94.8% women and 41.4% with non-coronary fibromuscular dysplasia (FMD)), 59 patients underwent genetic testing, of whom 3 (5.1%) received a diagnosis of connective tissue disorder: a 50-year-old man with Marfan syndrome; a 43-year-old woman with vascular Ehlers-Danlos syndrome and FMD; and a 45-year-old woman with vascular Ehlers-Danlos syndrome. An additional 12 patients (20.3%) had variants of unknown significance, none of which was thought to be a definite disease-causing mutation based on in silico analyses.

CONCLUSIONS

Only a minority of patients with SCAD who undergo genetic evaluation have a likely pathogenic mutation identified on gene panel testing. Even fewer exhibit clinical features of connective tissue disorder. These findings underscore the need for further studies to elucidate the molecular mechanisms of SCAD.