Echocardiographic consequences of smoking status in middle-aged subjects

Influence of cigarette smoking on biventricular systolic function independent of respiratory function: a cross-sectional study

Background

Cigarette smoking harms nearly every organ, including the heart and lungs. A comprehensive assessment of both cardiac and respiratory function is necessary for evaluating the direct effects of tobacco on the heart. However, few previous studies examining the effects of cigarette smoking on cardiac function included an assessment of lung function. This cross-sectional study investigated the influence of cigarette smoking on cardiac function, independent of respiratory function.

Methods

We retrospectively reviewed the medical records of 184 consecutive cases that underwent both spirometry and transthoracic echocardiography around the same time (within 1 month) in one hospital from April 2019 to March 2020. Participants were classified into three groups based on lifetime smoking exposure (pack-years): non-smoker (n = 49), low exposure (1–20 pack-years, n = 40), and high exposure (≥ 20 pack years, n = 95). Multiple linear regression analysis was used to assess the relationship among cigarette smoking, and cardiac and respiratory functions. The relationship between selected dependent variables and lifetime pack-years was assessed in two models with multiple linear regression analysis. Model 1 was adjusted for age and male sex; and Model 2 was adjusted for Model 1 plus forced expiratory volume percentage in 1 s and forced vital capacity percentage.

Results

Compared with the non-smokers, the participants with high smoking exposure had lower left ventricular (LV) systolic function and larger LV size. Multiple linear regression analysis revealed a negative association of cumulative lifetime pack-years with LV and right ventricular (RV) systolic functions, even after adjustment for age, sex, and spirometric parameters (forced expiratory volume percentage in 1 s and forced vital capacity percentage). Meanwhile, there was no significant association of smoking exposure with LV diastolic function (E/e′ and E/A) and RV diastolic function (e′t and e′t/a′t).

Conclusions

Cumulative smoking exposure was associated with a negative effect on biventricular systolic function in patients with relatively preserved cardiac function, independent of respiratory function.

Effect of present versus previous smoking on non-invasive haemodynamics

We examined cardiovascular function in 637 volunteers (19-72 years) without antihypertensive medication in never smokers (n = 365), present smokers (n = 81) and previous smokers (n = 191, median abstinence 10 years). Haemodynamics during passive head-up tilt were recorded using whole-body impedance cardiography and radial pulse wave analysis. Results were adjusted for age, sex, body mass index, LDL cholesterol and alcohol use. Systolic and diastolic blood pressure, heart rate, and pulse wave velocity were not different between the groups. Supine aortic reflection times did not differ, while upright values were shorter in present versus previous smokers (p = 0.04). Heart rate adjusted augmentation index was increased in the supine position in present smokers versus controls (p = 0.045), and in present (p < 0.001) and previous (p = 0.031) smokers versus controls in the upright position. Supine and upright cardiac output was higher (p ≤ 0.016) and systemic vascular resistance lower (p ≤ 0.001) in present versus previous smokers. In spite of the long abstinence, in the upright position previous smokers had lower cardiac output (p = 0.032) and higher systemic vascular resistance (p = 0.014) than never smokers. In the absence of differences in blood pressure and arterial stiffness, present smokers presented with hyperdynamic circulation and enhanced wave reflection compared with previous smokers.