Differential effects of heat-not-burn and conventional cigarettes on coronary flow, myocardial and vascular function

Abstract

We compared the effects of Heat-not-Burn cigarette (HNBC) to those of tobacco cigarette (Tcig), on myocardial, coronary and arterial function as well as on oxidative stress and platelet activation in 75 smokers. In the acute study, 50 smokers were randomised into smoking a single Tcig or a HNBC and after 60 min were crossed-over to the alternate smoking. For chronic phase, 50 smokers were switched to HNBC and were compared with an external group of 25 Tcig smokers before and after 1 month. Exhaled carbon monoxide (CO), pulse wave velocity (PWV), malondialdehyde (MDA) and thromboxane B2 (TxB2) were assessed in the acute and chronic study. Global longitudinal strain (GLS), myocardial work index (GWI), wasted myocardial work (GWW), coronary flow reserve (CFR), total arterial compliance (TAC) and flow-mediated dilation (FMD) were assessed in the chronic study. Acute HNBC smoking caused a smaller increase of PWV than Tcig (change 1.1 vs 0.54 m/s, p < 0.05) without change in CO and biomarkers in contrast to Tcig. Compared to Tcig, switching to HNBC for 1-month improved CO, FMD, CFR, TAC, GLS, GWW, MDA, TxB2 (differences 10.42 ppm, 4.3%, 0.98, 1.8 mL/mmHg, 2.35%, 19.72 mmHg%, 0.38 nmol/L and 45 pg/mL respectively, p < 0.05). HNBCs exert a less detrimental effect on vascular and cardiac function than tobacco cigarettes.Trial registration Registered on https://clinicaltrials.gov/ (NCT03452124, 02/03/2018).

Figure 1

Acute effects of heat-not-burn puffing versus tobacco cigarette smoking. Comparison between the acute effects of heat-not-burn versus tobacco cigarette smoking on (A) arterial stiffness, (B) oxidative stress burden, and (C) platelet activation status. HBNC showed a smaller increase of PWV than tobacco cigarette. All biomarkers are impaired following Tcig smoking, in contrast with HNBC puffing. PWV carotid-femoral pulse wave velocity, HNBC heat-not-burn cigarette, MDA malondialdehyde, Tcig tobacco cigarette, TxB2 thromboxane B2, SE Standard Error.

Figure 2

Progression of coronary flow reserve, flow mediated dilation, and myocardial work within 1 month of follow-up. Replacement of Tcig smoking with HNBC puffing for 1-month results in coronary and peripheral endothelial function improvement, along with wasted myocardial work reduction. CFR coronary flow reserve, FMD flow-mediated dilation, GWW global wasted work, SE Standard Error.

Figure 3

Coronary flow of left anterior descending artery at rest (left panel) and after adenosine infusion (right panel) for calculation of coronary flow reserve. Coronary flow of left anterior descending artery at rest (left panel) and after adenosine infusion (right panel) for calculation of coronary flow reserve at baseline (A) and after switching to HNBC for one month (B). The coronary flow reserve increased from 2.5 to 3.1 after 1 month of switching from tobacco cigarette to HNBC.

Figure 4

Flow chart of the study population. HNBC heat-not-burn cigarette, TCig tobacco cigarette.

Figure 5

Acute phase protocol. Following an initial sham smoking session, subjects were randomised to either a heat-not-burn or traditional cigarette smoking session; following a washout period of 60 min, they were crossed-over to the alternative smoking session. Each session was followed by a vascular stiffness examination and blood-sampling for oxidative stress and platelet activation assessment. Exam examination, HNBC heat-not-burn cigarette, TCig tobacco cigarette.