Left atrial function by cardiac computed tomography is a predictor of heart failure and cardiovascular death

Conduit Flow Compensates for Impaired Left Atrial Passive and Booster Functions in Advanced Diastolic Dysfunction

BACKGROUND

Quantification of left atrial (LA) conduit function and its contribution to left ventricular (LV) filling is challenging because it requires simultaneous measurements of both LA and LV volumes. The functional relationship between LA conduit function and the severity of diastolic dysfunction remains controversial. We studied the role of LA conduit function in maintaining LV filling in advanced diastolic dysfunction.

METHODS

We performed volumetric and flow analyses of LA function across the spectrum of LV diastolic dysfunction, derived from a set of consecutive patients undergoing multiphasic cardiac computed tomography scanning (n=489). From LA and LV time-volume curves, we calculated 3 volumetric components: (1) early passive emptying volume; (2) late active (booster) volume; and (3) conduit volume. Results were prospectively validated on a group of patients with severe aortic stenosis (n=110).

RESULTS

The early passive filling progressively decreased with worsening diastolic function (P<0.001). The atrial booster contribution to stroke volume modestly increases with impaired relaxation (P=0.021) and declines with more advanced diastolic function (P<0.001), thus failing to compensate for the reduction in early filling. The conduit volume increased progressively (P<0.001), accounting for 75% of stroke volume (interquartile range, 63-81%) with a restrictive filling pattern, compensating for the reduction in both early and booster functions. Similar results were obtained in patients with severe aortic stenosis. The pulmonary artery systolic pressure increased in a near-linear fashion when the conduit contribution to stroke volume increased above 60%. Maximal conduit flow rate strongly correlated with mitral E-wave velocity (r=0.71; P<0.0001), indicating that the increase in mitral E wave in diastolic dysfunction represents the increased conduit flow.

CONCLUSIONS

An increase in conduit volume contribution to stroke volume represents a compensatory mechanism to maintain LV filling in advanced diastolic dysfunction. The increase in conduit volume despite increasing LV diastolic pressures is accomplished by an increase in pulmonary venous pressure.

Vascular Health Promotion Project and Vascular Medicine in China-CCVM2004-2023

Cardiovascular disease(CVD) has become a major disease burden affecting people's health in China. Blood vessels are very important for human health and are the "sentinel" for the development of many cardiovascular and cerebrovascular diseases. The key to effectively preventing fatal, disabling heart, brain and peripheral vascular events lies in controlling traditional and non-traditional risk factors for vascular health from the source, and early assessment and intervention of early vascular lesions. Since 2004, China government promoted the early detection technology of vascular lesions and vascular medicine, and proposed the Beijing Vascular Health Stratification (BVHS) to provide suggestions for the examination, evaluation and management of risk factors, and to provide new ideas for lifelong maintenance of vascular health. This review mainly introduces the establishment and development of the clinical discipline of "vascular medicine" in the past 20 years in China, introduces the indicators for detecting vascular function and structure and the predictive value of vascular events, and carries out intelligent and digital management of vascular health throughout the life cycle of individualized prevention, treatment and rehabilitation for people with different parts or degrees of lesions, effectively reducing the occurrence and development of cardiovascular and cerebrovascular diseases, and the prospect of new technology in maintaining vascular health.

Comparison Between Echocardiography and Cardiac Computed Tomography in the Evaluation of Diastolic Dysfunction and Prediction of Heart Failure

Recent data indicate that left atrial (LA) function assessment by cardiac computed tomography (CT) is closely related to diastolic dysfunction (DD). Therefore, we aimed to perform a direct comparison between CT and echocardiography for diagnosis of advanced DD and prediction of future heart failure or cardiovascular death. We identified 340 patients who had both spiral cardiac CT and a proximate echocardiogram. LA total emptying fraction (LATEF), a measure of global LA function, was automatically calculated from CT data, as a surrogate for diastolic function and was compared with echocardiographic grades of diastolic function. The area under the receiver operating characteristic curve for LATEF to differentiate between advanced DD (grades 2 and 3) and all other grades was 0.84 (0.79 to 0.88). Over a median of 4 years, 69 events (admissions for heart failure and cardiovascular deaths) occurred. By multivariate Cox analysis, LATEF <40% provided incremental prognostic information after adjustments for advanced DD by echocardiography (hazard ratio 2.15, 95% confidence interval 1.13 to 3.94). There was a significant interaction (p = 0.03) between LATEF and echocardiography-based diastolic grades. Stratified analyses within the diastolic function groups revealed that LATEF <40% was equivalent to echocardiography in predicting events in the subgroup with advanced DD by echocardiography (p = 0.20) but was associated with a significantly higher event rates in patients with normal filling pressures (p = 0.0001) or indeterminate diastolic function (p = 0.04) by echocardiography. In conclusion, LA function derived from CT can accurately detect advanced DD diagnosed by echocardiography and has additive value to echocardiography-derived DD.