The Impact of Khat (Catha edulis) on Hemodynamics of the Common Carotid Arteries in Regular Khat Chewers: A Case-control Study Using Doppler Ultrasound.

BACKGROUND: To evaluate the effect of chewing khat on the hemodynamics of the common carotid arteries (CCAs) using Doppler ultrasound imaging.
METHODS: This is a cross-sectional case-control study. Fifty volunteers who were chronic regular khat chewers were selected and compared with healthy nonkhat chewers. They were examined using Doppler imaging with a 7-10 MHz linear transducer. The resistivity index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end-diastolic velocity of the CCAs were determined according to the standard protocol of carotid Doppler ultrasound.
RESULTS: The RI and PI of the right and left CCAs were significantly higher in khat chewers compared to controls (P < 0.001). The PSV of the right and left CCAs was considerably higher in khat chewers compared to controls (P < 0.001 and 0.04, respectively).
CONCLUSION: The Doppler values of blood flow velocity, resistivity, and pulsatility were significantly higher in chronic regular khat chewers compared to nonkhat chewers. Khat is a significant contributory factor for increasing the hemodynamics of the CCAs. Copyright:

INTRODUCTION

Catha edulis (commonly known as khat or qat) is a plant that produces a psychoactive substance that contains cathine and cathinone and has a similar structure and action to amphetamine.[1] Khat grows in equatorial climates, such as Africa and the Arabian Peninsula.[23] C. edulis belongs to the Celastraceae family.[4] Cathine and cathinone are responsible for increasing heart rate (HR) and blood pressure (BP).[5]

Regular khat consumption has been associated with elevated HR and BP. Khat chewers reportedly had a higher risk of various cardiovascular diseases, such as cardiogenic shock, recurrent myocardial ischemia, and ventricular arrhythmia.[6] Khat chewing is also associated with stroke and hypertension.[67] Therefore, studying the hemodynamics of the common carotid arteries (CCAs) may contribute to predicting cerebrovascular abnormalities.

Only a few attempts have been made to explain the relationship between khat and cardiovascular disease. Studying the influence of khat on hemodynamics is very important, since the elevation of HR and BP may lead to peripheral vascular events. Studying the effects of khat on carotid hemodynamics may be helpful in detecting cerebrovascular problems of the brain. Currently, few studies in literature demonstrate the impact of khat on hemodynamics of the CCAs. The ultimate aim of this study is to evaluate the impact of khat on the hemodynamics of the CCAs in regular khat chewers.

MATERIALS AND METHODS

This was a prospective, case–control study designed to investigate the impact of khat (C. edulis) on the hemodynamics of the CCAs using duplex ultrasound. The study was performed at Kaah Community Hospital in Hargeisa, Somaliland, between September 2017 and December 2017. The study was approved by the Ethical Committee Board of the National Ribat University (IRB approval no. RNU112017), and informed consent was obtained from all participants. The study compared 50 volunteers (48 males and 2 females) who were regularly chewing khat with 50 asymptomatic volunteers (47 males and 3 females) who did not chew khat as the control group. The khat chewers consumed amount of 100–300 g of qat fresh leaves which were regularly chewed per day. The sample size was selected using a simple and convenient systematic sampling method. A designed data collection sheet was used to collect demographic and clinical data, such as clinical history, the status of chewing khat, and the duration of chewing khat. Participants with diabetes mellitus, hypertension, renal and cardiac diseases, and stenosis of the carotid arteries were excluded since these abnormalities could influence the blood flow velocities of the carotid arteries.

The Doppler sonographic procedure

The Doppler investigations were performed using DC-N3 ultrasound equipment (Mindray, China) with a linear high-frequency transducer (7–10 MHz). The B-mode settings were adjusted to optimize the image quality before applying the Doppler imaging. Both right and left CCAs were examined using duplex ultrasound.

The participants were investigated in the supine position with the head extended upward and turned away from the side being examined. Doppler parameters were adjusted to optimize good signal intensity. Pulsed wave Doppler measurements were performed using a sample volume that covered the one-third width of the vessel lumen. Flow velocities were recorded once the signal was stable for at least 5 s. The Doppler frequencies were performed by adjusting the angle of the Doppler beam at the course of the artery. The Doppler wave measurements were analyzed and stored using the hard drive of the ultrasound equipment and computer. The Doppler flow velocities were measured in each CCA as follows: (1) peak systolic velocity (PSV) and (2) maximum end-diastolic velocity (EDV). The resistivity index (RI) and pulsatility index (PI) were automatically calculated by the ultrasound machine.

Statistical analysis

The statistical analysis was performed using the Statistical Package for the Social Sciences version 16.0 (IBM, Cary, North Carolina, USA). The independent t-test was used to compare the Doppler indices of the CCAs between the khat chewers and the controls. Qualitative data were described by means and frequencies. P < 0.05 was considered statistically significant.

RESULTS

Fifty regular khat chewers were investigated in this study. There were 48 (96%) males and only 2 (4%) females. Table 1 summarizes the demographic characteristics of the khat users and the controls. The mean age of the khat users was 35.9 ± 9 years, whereas the mean age of the controls was 30.86 ± 7 years old. The majority of the khat chewers were in the 31–40-year-old age group. The mean duration of khat chewing was 15.68 ± 8 years, as calculated from the duration groups.

Table 1

Demographic characteristics of the study population

	Khat chewers (n=50)	Controls (n=50)	P
Men, n (%)	48 (96)	47 (94)	0.65
Mean age (years), n (%)	34.58±8.4	32.8±10.6	0.36
<20	5 (10)	10 (20)
21-30	11 (22)	18 (36)	.02
31-40	16 (32)	13 (26)
41-50	10 (20)	9 (18)
51-60	8 (16)
Mean duration of khat chewing (years), n (%)	15.68 ± 8 years
<5	7 (14)
5-15	21 (28)
16-25	17 (34)
26-35	5 (10)

Table 2 summarizes the comparison of CCA hemodynamics in regular khat chewers and controls. The RI and PI of the right and left CCAs were significantly higher in khat chewers compared to controls (P < 0.001). The PSV was significantly higher in the right and left CCAs (89.31 ± 10.66 vs. 76.47 ± 9.87 cm/s and 84.78 ± 12.032 vs. 80.47 ± 8.90 cm/s; P < 0.001 and 0.04, respectively). The EDV of the right and left CCAs was also higher in cases compared to controls (18.13 ± 2.24 vs. 15.58 ± 2.58 cm/s and 17.51 ± 1.70 vs. 16.99 ± 2.60 cm/s, respectively). Overall, the Doppler values of the carotid blood velocities were significantly higher in the khat chewers compared to the nonkhat chewers.

Table 2

Comparison of Doppler indices of the common carotid arteries in khat chewers and controls

	Khat chewers	Controls	P
Right CCA
PSV (cm/s)	89.31±10.66	76.47±9.87	<0.001
EDV (cm/s)	18.13±2.24	15.58±2.58	<0.001
RI	0.82±0.04	0.79±0.03	<0.001
PI	2.28±0.37	2.01±0.32	<0.001
Left CCA
PSV (cm/s)	84.78±12.032	80.47±8.90	0.04
EDV (cm/s)	17.51±1.70	16.99±2.60	0.24
RI	0.80±0.04	0.77±0.05	<0.001
PI	2.39±0.43	2.33±0.35	0.42

CCA: Common carotid artery, RI: Resistivity index, PI: Pulsatility index, PSV:Peak systolic velocity, EDV: End-diastolic velocity

Age and gender had no significant correlation with Doppler parameters of CCAs in chronic regular khat chewers (P < 0.05) as shown in Table 3. The correlations were very weak. The insignificant and weak correlation excluded the impact of age and gender on hemodynamics of the CCAs in this sample study.

Table 3

Correlation of gender and age with Doppler parameters in regular khat chewers

	Gender		Age
	Correlation coefficient (r)	P	Correlation coefficient (r)	P
Right CCA
PSV (cm/s)	−0.022	0.825	0.035	0.729
EDV (cm/s)	−0.093	0.357	−0.096	0.340
RI	−0.052	0.605	0.060	0.550
PI	−0.024	0.812	−0.024	0.809
Left CCA
PSV (cm/s)	−0.184	0.067	−0.179	0.075
EDV (cm/s)	0.051	0.614	−0.108	0.286
RI	0.063	0.536	0.014	0.894
PI	0.120	0.235	0.064	0.530

CCA: Common carotid artery, RI: Resistivity index, PI: Pulsatility index, PSV: Peak systolic velocity, EDV: End-diastolic velocity

Figure 1 summarizes the comparison of systolic and diastolic BPs between khat chewers and controls. They were significantly higher in the khat chewers than the controls (P < 0.05). Figure 2 summarizes the comparison of HR between khat chewers and controls. The HR was significantly increased in khat chewers than controls (P < 0.05).

Figure 1

Comparison of systolic and diastolic blood pressure between qat chewers and controls. *Significance at the 0.05 level (two-tailed)

Figure 2

Comparison of heart rate between qat chewers and controls. *Significance at the 0.05 level (two-tailed)

DISCUSSION

Considering the growing prevalence of khat chewing worldwide, the implications are essential since abnormal elevation in HR and BP are considered key risk factors for the pathogenesis of cardiovascular and cerebrovascular lesions.[89] Besides the rise in BP and HR that have been well demonstrated in previous studies, the current study revealed that the Doppler indices of the CCAs were changed in regular khat chewers. The insignificant and weak correlation which we found in this study excluded the impact of age and gender on hemodynamics of the CCAs.

In the current study, it was found that the Doppler indices RI and PI were significantly elevated in khat chewers compared to controls (P < 0.001). There is only one study in the literature demonstrating the effect of khat on the hemodynamics of the CCAs; it revealed the immediate influence of chewing khat on RI and PI. Ibrahim et al. studied the immediate effect of khat on the hemodynamics of the CCAs using Doppler imaging. They found that the RI and PI were significantly lower after chewing khat.[10] They studied the influence for 2 h before and after chewing khat. In contrast, the RI and PI in the current study increased significantly due to the long-term use of khat for several years. There are no existing studies to compare these findings with. In previous studies, khat was reported to affect the coronary arteries and caused marked vasoconstriction.[11] The same effect may happen in the CCAs and cause elevation of the CCA Doppler indices. This effect might be attributed to the peripheral vasoconstrictor effect of cathinone,[64712] which may be persistent for a long time in regular khat chewers.

The current study demonstrated that the PSV and EDV of the CCAs were significantly elevated in the khat chewers compared to the controls. Consistent with this finding, Ibrahim et al. revealed a significant effect of khat on the blood hemodynamics of the CCAs. They reported that the PSV and EDV increased after chewing khat.[10] The elevation of blood flow velocity might be attributed to increased HR and BP as a consequence of chewing khat. Abnormal carotid flow velocities and pulsatility may be associated with cardiovascular events.[1314]

The difference and mechanism between immediate and long-term effect of khat is governed by the duration of khat chewing. Long duration of khat chewing accumulates considerable amount of cathine and cathinone which are responsible for alterations flow velocities and resistances. It was reported that a duration of 4 h causes increased BP and HR with decreased RI and PI.[10] Another study reported that the long term of khat chewing was significantly associated with increased systolic BP and diastolic BP.[8] Consequently, the increased BP would elevate the Doppler parameters. Unfortunately, no previous studies have demonstrated the impact of khat on blood flow velocity in the CCAs.

In general, there is not much research in the literature concerning the impact of khat on the hemodynamics of blood vessels. Considering the effect of khat on the coronary arteries, as stated in the literature, we suggest that the same events might occur in the carotid arteries. The implications of khat on the heart may produce a considerable effect on the hemodynamics of the peripheral arteries, such as the CCAs.

This study faced major limitations since it was a single-center study. Second, the majority of khat chewers were also smokers. We found difficulty in excluding smokers. Therefore, this affected the sample size, which was not large enough. Furthermore, no previous studies have demonstrated the effect of khat on the hemodynamics of the carotid vessels. To assess the effect of chronic khat chewing on hemodynamics of CCAs, further studies with larger sample size need to be undertaken.

CONCLUSION

The values of the blood flow velocity parameters of the carotid arteries were significantly elevated in regular khat chewers. Understanding the impact of khat on carotid artery hemodynamics is essential in the prediction of cerebrovascular abnormalities.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.