Trial Outcomes & Findings for The Cardiovascular Effects of Electronic Hookah Vaping (NCT NCT03690427)

Participants were recruited through advertisements posted at Southern California colleges and universities, as well as social media websites, from December 2018 to August 2020.

The Cardiovascular Effects of Electronic Hookah Vaping

Using ultrasound, FMD of the brachial artery induced by reactive hyperemia, was used to measure endothelium-dependent vasodilator function. Baseline diameter and velocity were recorded for 45 seconds and resumed 30 seconds before cuff deflation and continuously for 2 minutes after deflation to obtain true peak vasodilatory response.

Using applanation tonometry, cf-PWV was used to measure central arterial stiffness.

Capacity was determined as the ability of HDL to inhibit LDL-induced oxidation of dihydrodichlorofluorescein into the fluorescent dichlorofluorescein. Capacity was expressed as an HDL oxidative index, determined by the ratio of dichlorofluorescein fluorescence in the presence and absence of HDL. An index of \< 1.0 denotes protective antioxidant HDL, whereas an index of \> 1.0 indicates pro-oxidant HDL.

PON-1 activity was determined by the ability of PON-1, associated with HDL, to hydrolyze paraoxon substrate. The hydrolysis of paraoxon (diethyl-p-nitrophenyl phosphate) to p-nitrophenol by PON-1 was determined by incubating 5 mL of plasma with 1.0 mM paraoxon in 100 mM tris-HCl buffer (pH, 8.5). Unit of Measure: expressed as micromoles of p-nitrophenol formed per minute for every 1 mL plasma.

Arylesterase activity (lipid peroxidation biomarker) was determined by the rate of hydrolysis of phenyl acetate to phenol. Briefly, 4 mL plasma was incubated with 3.5 mM phenyl acetate in 9 mM Tris-HCl buffer (pH, 8.0) containing 0.9 mM CaCl2 at RT. The kinetics of phenol formation were determined by recording the absorbance at 270 nm every 15 s for 2 min. Unit of Measure: nanomoles of product formed per minute per milliliter of plasma.

Plasma hs-CRP (inflammatory biomarker)

Plasma TNFα (inflammatory biomarker)

Using ultrasound, FMD of the brachial artery, induced by reactive hyperemia, was used to measure endothelium-dependent vasodilator function after intravenous infusion of antioxidant ascorbic acid. Infusion of antioxidant ascorbic acid was done before the e-hookah vaping session.

As a control test for the assessment of endothelium-dependent vasodilator function, using ultrasound the brachial artery, endothelium-independent dilatation was assessed by administering sublingual nitroglycerin. This measure was assessed 10 minutes after FMD testing. Ultrasound images were recorded continuously for a total of 10 minutes

AI was used to measure central stiffness. It was calculated as the ratio of augmentation pressure (difference between the second and first systolic peaks of the aortic pressure waveform) and pulse pressure expressed as a percentage.

Plasma IL-6 (inflammatory biomarker).

Serum IL-10 (anti-inflammatory biomarker)

Plasma nicotine levels (smoking or vaping exposure biomarker)

Exhaled CO levels (smoking or vaping exposure biomarker)