High Prevalence of Severe Aortic Stenosis in Low-Flow State Associated With Atrial Fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a low-flow state and may underestimate aortic stenosis (AS) severity. Single-high Doppler signals (HS) consistent with severe AS (peak velocity ≥4 m/s or mean gradient ≥40 mm Hg) are averaged down in current practice. The objective for the study was to determine the significance of HS in AF low-gradient AS (LGAS). METHODS: One thousand five hundred forty-one patients with aortic valve area ≤1 cm2 and left ventricular ejection fraction ≥50% were identified and classified as high-gradient AS (HGAS) (≥40 mm Hg) and LGAS (<40 mm Hg), and AF versus sinus rhythm (SR). Available computed tomography aortic valve calcium scores (AVCS) were retrieved from the medical record. Outcomes were assessed. RESULTS: Mean age was 76±11 years, female 47%. Mean gradient was 51±12 in SR-HGAS, 48±10 in AF-HGAS, 31±5 in SR-LGAS, and 29±7 mm Hg in AF-LGAS, all P≤0.001 versus SR-HGAS; HS were present in 33% of AF-LGAS. AVCS were available in 34%. Compared with SR-HGAS (2409 arbitrary units; interquartile range, 1581-3462) AVCS were higher in AF-HGAS (2991 arbitrary units; IQR1978-4229, P=0.001), not different in AF-LGAS (2399 arbitrary units; IQR1817-2810, P=0.47), and lower in SR-LGAS (1593 arbitrary units; IQR945-1832, P<0.001); AVCS in AF-LGAS were higher when HS were present (P=0.048). Compared with SR-HGAS, the age-, sex-, comorbidity index-, and time-dependent aortic valve replacement-adjusted mortality risk was higher in AF-HGAS (hazard ratio=1.82 [1.40-2.36], P<0.001) and AF-LGAS with HS (hazard ratio=1.54 [1.04-2.26], P=0.03) but not different in AF-LGAS without HS or SR-LGAS (both P=not significant). CONCLUSIONS: Severe AS was common in AF-LGAS. AVCS in AF-LGAS were not different from SR-HGAS. AVCS were higher and mortality worse in AF-LGAS when HS were present.

Assessment of left ventricular filling pressure with Doppler velocities across the patent foramen ovale.

BACKGROUND: The utility of Doppler velocities across the patent foramen ovale (PFO) to estimate left ventricular (LV) filling pressure is not well known. METHODS: The best cut-off value of peak interatrial septal velocity across a transeptal puncture site measured by transesophageal echocardiography for estimating high mean left atrial (LA) pressure (≥ 15 mmHg) was determined in 17 patients. This cut-off value was subsequently applied to 67 patients with a PFO undergoing transthoracic echocardiography (TTE) for assessing the value of PFO velocity in determining LV filling pressure. RESULTS: The peak systolic interatrial septal velocities significantly correlated with directly measured mean LA pressures during transcatheter mitral valve procedure (r = 0.77, P < 0.001). The best cut-off value was 1.7 m/s for predicting high LA pressure (AUC 0.91; sensitivity 90%, specificity 86%). When this cut-off was applied to patients undergoing TTE, peak PFO velocity ≥ 1.7 m/s correlated with reduced e', higher E/e', and higher tricuspid regurgitation velocity (P < 0.01). LV filling pressure according to the 2016 diastolic guideline was compared with peak PFO velocity in 51 patients. Among patients with high filling pressure according to the guidelines (n = 20), peak PFO velocity ≥ 1.7 m/s was present in 60% of patients. In patients with normal filling pressure per the guidelines (n = 31), PFO velocity < 1.7 m/s was present 84%. Sensitivity and specificity were 75% and 92%, respectively, in patients with sinus rhythm, but were only 50% and 57%, respectively, among patients with atrial fibrillation. CONCLUSIONS: Doppler-derived peak PFO velocities could be valuable in the assessment of increased LV filling pressure using 1.7 m/s as the cut-off value.

Impact of Anemia on Exercise and Pharmacologic Stress Echocardiography.

BACKGROUND: The safety and diagnostic accuracy of stress testing in anemic patients have not been well studied. Despite a lack of data, significant anemia may be considered a relative contraindication to stress testing because of safety concerns related to insufficient myocardial oxygen supply. METHODS: The authors reviewed 28,829 consecutive patients with blood hemoglobin drawn within 48 hours of stress echocardiography (15,624 exercise and 13,205 dobutamine). The associations of blood hemoglobin concentration with arrhythmia and other stress echocardiographic findings were examined. Additionally, the effect of anemia on the positive predictive value of stress echocardiography for the detection of significant coronary artery stenosis (≥50%) was assessed in patients who subsequently underwent coronary angiography. RESULTS: Anemia was present in 6,401 patients (22.2%) and was severe (hemoglobin < 8.0 g/dL) in 52. Stress testing with either exercise or dobutamine was safe, with no significant increase in serious arrhythmia events or need for hospitalization. In the exercise cohort, worsening anemia was associated with reduced treadmill exercise time, lower peak heart rate, peak rate-pressure product, and achieved workload. In the dobutamine stress cohort, worsening anemia was associated with higher resting heart rate, more use of atropine, and fewer patients attaining target heart rate. The positive predictive value of stress echocardiography was higher in patients with moderate anemia compared with those without anemia (71.8% vs 60.2%, P = .01). CONCLUSIONS: This study demonstrates that stress testing is safe in patients with mild and moderately anemia, albeit with a small increase in mild supraventricular arrhythmias with exercise. However, worsening anemia was associated with a significant reduction in exercise capacity. Additionally, worsening anemia was associated with an improvement in the positive predictive value of stress echocardiography. Extrapolation of these data to patients with severe anemia should be performed with caution given the limited number of patients with severe anemia in this study.

Contribution of mitral valve leaflet length and septal wall thickness to outflow tract obstruction in patients with hypertrophic cardiomyopathy.

We sought to examine whether elongation of the mitral valve leaflets in patients with hypertrophic cardiomyopathy (HCM) is synergistic to septal wall thickness (SWT) in the development of left ventricular outflow tract obstruction (LVOTO). HCM is a common genetic cardiac disease characterized by asymmetric septal hypertrophy and predisposition towards LVOTO. It has been reported that elongation of the mitral valve leaflets may be a primary phenotypic feature and contribute to LVOTO. However, the relative contribution of this finding versus SWT has not been studied. 152 patients (76 with HCM and 76 non-diseased age, race and BSA-matched controls) and 18 young, healthy volunteers were studied. SWT and the anterior mitral valve leaflet length (AMVLL) were measured using cine MRI. The combined contribution of these variables (SWT × AMVLL) was described as the Septal Anterior Leaflet Product (SALP). Peak LVOT pressure gradient was determined by Doppler interrogation and defined as "obstructive" if ≥ 30 mmHg. Patients with HCM were confirmed to have increased AMVLL compared with controls and volunteers (p < 0.01). Among HCM patients, both SWT and SALP were significantly higher in patients with LVOTO (N = 17) versus without. SALP showed modest improvement in predictive accuracy for LVOTO (AUC = 0.81) among the HCM population versus SWT alone (AUC = 0.77). However, in isolated patients this variable identified patients with LVOTO despite modest SWT. Elongation of the AMVLL is a primary phenotypic feature of HCM. While incremental contributions to LVOTO appear modest at a population level, specific patients may have dominant contribution to LVOTO. The combined marker of SALP allows for maintained identification of such patients despite modest increases in SWT.

Radiographic monitoring of incidental abdominal aortic aneurysms: a retrospective population-based cohort study.

BACKGROUND: An abdominal aortic aneurysm (AAA) that is identified when the abdomen is imaged for some other reason is known as an incidental AAA. No population-based studies have assessed the management of incidental AAAs. The objective of this study was to measure the completeness of radiographic monitoring of incidental AAAs by means of a population-based analysis. METHODS: We linked a cohort of patients with incidental AAA (defined as a previously unidentified aortic enlargement exceeding 30 mm in diameter found in an imaging study performed for another reason) to various population-based databases. We followed the patients to elective repair or rupture of the aneurysm, death or 31 Mar. 2009. We used evidence-based monitoring guidelines to calculate the proportion of observation time during which each incidental AAA was incompletely monitored. We used negative binomial regression to determine the association of patient-related factors with this outcome. RESULTS: For the period between January 1996 and September 2008, we identified 191 patients with incidental AAA (mean diameter 37.6 mm, 95% confidence interval [CI] 36.6-38.6 mm; median follow-up 4.4 [range 0.6-12.7] years). Fifty-six of these patients (29.3%) had no radiographic monitoring of the aneurysm. Overall, patients spent one-fifth of their time with incomplete monitoring of the AAA (median 19.4%, interquartile range 0.3%-44.0%). Factors independently associated with incomplete monitoring included older age (relative rate [change in proportion of time with incomplete monitoring] [RR] 1.27, 95% CI 1.10-1.47, per decade), larger size (RR 1.65, 95% CI 1.38-2.01, per 10-mm increase) and detection of the aneurysm while the patient was in hospital or the emergency department (RR 1.34, 95% CI 1.00-1.79). Comorbidities were not associated with monitoring. INTERPRETATION: Radiographic monitoring of incidental AAAs was incomplete, and almost one-third of patients underwent no monitoring at all. Incomplete monitoring did not appear to be related to patients' comorbidity.

The influence of incidental abdominal aortic aneurysm monitoring on patient outcomes.

BACKGROUND: Incidental abdominal aortic aneurysms (AAAs) are identified when the abdomen is imaged for other reasons. These are common, and many undergo incomplete radiological monitoring. The association between monitoring completeness and population-based outcomes has not been studied. METHODS: A cohort of incidental AAAs (defined as previously unidentified aortic enlargement exceeding 3 cm found on an imaging study done for another reason) was linked to population-based data. Patients were followed to elective AAA repair, AAA rupture, death, or March 31, 2009. Monitoring completeness was gauged as the sequential number of months without a recommended abdominal scan. Its association with time to elective AAA repair and time to death was measured using a multivariable Cox regression model adjusting for other important covariates. RESULTS: We identified 191 incidental AAAs between 1996 and 2004 (median diameter of 3.5 cm [range, 3.0-5.3 cm], median follow up of 4.4 years [range, 0.6-12.7 years]). During the study, patients spent a median of 19.4% of their time with incomplete AAA monitoring (interquartile range [IQR] 0.3%-44%); 56 patients (29.3%) had no follow-up imaging of their aneurysm. Nineteen patients (10.0%; 2.0% per year) underwent elective AAA repair, and 79 patients (37.7%; 7.6% per year) died. Independent of important covariates, people were significantly less likely to undergo elective repair (hazard ratio [HR], 0.03) and significantly more likely to die (HR, 2.99) if their AAA went without radiological monitoring for 1 year. CONCLUSIONS: Incomplete incidental AAA radiological monitoring was significantly associated with a decreased risk of elective AAA repair and an increased risk of death. While uncontrolled confounding might explain part of these associations, clinicians should ensure that radiological monitoring of AAAs is complete in appropriate patients.

Incidence, follow-up, and outcomes of incidental abdominal aortic aneurysms.

BACKGROUND: Incidental abdominal aortic aneurysms (AAAs) are identified during imaging for other reasons. Incidental AAAs are important findings because they require monitoring and surgical treatment, when indicated, to prevent rupture. The prevalence of incidental AAAs and their management has not been extensively studied. METHODS: We electronically screened a 25% simple random sample of abdominal computed tomography (CT), ultrasound (US), and magnetic resonance imaging (MRI) studies conducted between 1996 and 2008 at one academic medical center. Screen-positive reports were manually reviewed to determine if they showed an incidental AAA. We reviewed the medical records of all in-patients to determine whether the incidental AAA was documented, a treatment plan was identified, and whether it was communicated to the patient's family physician through the discharge summary. We used evidence-based recommended schedules to determine the adequacy of AAA monitoring for each person. RESULTS: In 79,121 abdominal images, we identified 812 incidental AAAs (1.0% of all studies) or 364 incidental AAAs annually (95% confidence interval [CI], 349-379). Patients were elderly (mean age, 74 years), and AAAs were a mean diameter of 4.0 cm. For 174 inpatients, AAAs were noted in only 51 patients (29%) and only 25 (15%) were communicated to the family physician. Of 329 patients who were observed beyond their first recommended follow-up scan, only 51 (16%) were monitored appropriately throughout their entire follow-up; the median proportion of follow-up time with recommended monitoring was 56% (interquartile range, 32%-82%). Elective AAA repair was done in 98 patients (13%), the probability of which was significantly increased when AAA monitoring frequency was compliant with that recommended in practice guidelines. Six patients (0.8%) were admitted with aortic rupture, the probability of which was independent of AAA monitoring. CONCLUSION: Incidental AAAs are common and appear to be poorly monitored. Our data suggested that improved monitoring of incidental AAAs was independently associated with elective AAA repair. Population-based analyses are required to determine the influence that monitoring has on incidental AAA rupture and patient mortality.