August 31, 2019

Stanton A. Glantz, PhD

More evidence that e-cigs harm the cardiovascular system in healthy young adults – and it’s not the nicotine

Alessandra Caporale and colleagues recently published “Acute Effects of Electronic Cigarette Aerosol Inhalation on Vascular Function Detected at Quantitative MRI” that shows that exposure to nicotine free e-cigarette aerosol immediately inhibits normal function of blood vessels in ways similar to exposure to cigarette smoke or secondhand cigarette smoke.

They had 31 young adult never-smokers who were in good health use a nicotine-free e-cigarette, then measured the ability of their blood vessels to dilate (get bigger) in response to increased demands for blood flow.  There was also evidence that their arteries got stiffer.  These effects appeared immediately after using the e-cigarette.

These changes (reductions in so-called flow mediated dilation) are a risk factor for long-term development of heart disease and, if it occurs in people at risk of a heart attack, can be involved in triggering an event.

The fact that they found these effects in nicotine-free aerosol is more evince that other elements of the e-cigarette aerosol are causing the problems.

Here is the abstract:

Background Previous studies showed that nicotinized electronic cigarettes (hereafter, e-cigarettes) elicit systemic oxidative stress and inflammation. However, the effect of the aerosol alone on endothelial function is not fully understood. Purpose To quantify surrogate markers of endothelial function in nonsmokers after inhalation of aerosol from nicotine-free e-cigarettes. Materials and Methods In this prospective study (from May to September 2018), nonsmokers underwent 3.0-T MRI before and after inhaling nicotine-free e-cigarette aerosol. Peripheral vascular reactivity to cuff-induced ischemia was quantified by temporally resolving blood flow velocity and oxygenation (SvO2) in superficial femoral artery and vein, respectively, along with artery luminal flow-mediated dilation. Precuff occlusion, resistivity index, baseline blood flow velocity, and SvO2 were evaluated. During reactive hyperemia, blood flow velocity yielded peak velocity, time to peak, and acceleration rate (hyperemic index); SvO2 yielded washout time of oxygen-depleted blood, rate of resaturation, and maximum SvO2 increase (overshoot). Cerebrovascular reactivity was assessed in the superior sagittal sinus, evaluating the breath-hold index. Central arterial stiffness was measured via aortic pulse wave velocity. Differences before versus after e-cigarette vaping were tested with Hotelling T2 test. Results Thirty-one healthy never-smokers (mean age, 24.3 years ± 4.3; 14 women) were evaluated. After e-cigarette vaping, resistivity index was higher (0.03 of 1.30 [2.3%]; P < .05), luminal flow-mediated dilation severely blunted (-3.2% of 9.4% [-34%]; P < .001), along with reduced peak velocity (-9.9 of 56.6 cm/sec [-17.5%]; P < .001), hyperemic index (-3.9 of 15.1 cm/sec2 [-25.8%]; P < .001), and delayed time to peak (2.1 of 7.1 sec [29.6%]; P = .005); baseline SvO2 was lower (-13 of 65 %HbO2 [-20%]; P < .001) and overshoot higher (10 of 19 %HbO2 [52.6%]; P < .001); and aortic pulse wave velocity marginally increased (0.19 of 6.05 m/sec [3%]; P = .05). Remaining parameters did not change after aerosol inhalation. Conclusion Inhaling nicotine-free electronic cigarette aerosol transiently impacted endothelial function in healthy nonsmokers. Further studies are needed to address the potentially adverse long-term effects on vascular health.

The full citation is: Caporale A, Langham MC, Guo W, Johncola A, Chatterjee S, Wehrli FW.  Acute Effects of Electronic Cigarette Aerosol Inhalation on Vascular Function Detected at Quantitative MRI.  Radiology. 2019 Aug 20:190562. doi: 10.1148/radiol.2019190562. [Epub ahead of print].  It is available here.


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