This study found that the prevalence of sIAD was high as 18.6% in these post-stroke patients with hemiparesis. Based on 16 studies, Clark et al. pointed out that the pooled estimates of prevalence for sIAD ≥10 mmHg were 11.2% in hypertension, 7.4% in diabetes, and 3.6% for a general adult population[16]. Another study showed that the prevalence rates of sIAD≥10 mmHg were 12.8% in Chinese community hypertensive population[17]. The prevaluence of IAD in this population was higher as compared with the previous reports. As sIAD ≥10mm Hg is associated with poor outcome and high burden of cerebral small-vessel diseases in the post-stroke patients [14,18-20], bilateral BP measurement in the post-stroke patients is necessary to screen the sIAD. Thus, we encourage to measure bilateral arm BP at first to screen IAD.
According to the current hypertension guidelines, bilateral arm BP should be measured at first to identify a reference arm for subsequent BP measurement. However, almost physicians and nurses use the unaffected arm for BP measurement in the post-stroke patients with hemiparesis, at least in China [15]. Our study found in these patients, the possibility of reference arm assigned on the unaffected arm or on the paretic arm was almost the same (194 cases vs 191cases). These results mean that the paretic arm may have not obvious patho-physiological abnormality, at least in rehabilitation period.
Furthermore, the present study also demonstrated that the mean SBP and DBP levels measured on the reference arm were significantly higher by 2.9/2.4 mm Hg than those on the unaffected arm. When using the SBP values from unaffected arm, the detection rate of systolic hypertension was 35.2%, while this rate increased to 40.0% when using the values from reference arm, and there was a difference of 5 percentages. In other words, of the 168 patients with true hypertension, 22 patients were misdiagnosed as normotensives when using the BP values of unaffected arm. These results clearly indicted that using the unaffected arm to measure BP may miss the diagnosis of hypertension in post-stroke patients with hemiparesis. Therefore, we suggest that bilateral arm BP measurement at first to identify the reference arm, and the BP values measured on the reference arm are used for hypertension diagnosis [1,2]. A previous study enrolled 236 post-stroke patients with hemiplegic paralysis and found that the paralyzed arm had similar mean SBP and DBP levels as compared with the unaffected arm[21].
Clinical implications
It is important to screen IAD in the post-stroke patients even in the rehabilitation period with bilateral arm BP measurement, the traditional approach to using unaffected arm for BP measurement is not reasonable, as this method could not detect IAD at first, meanwhile, using the unaffected arm for BP measurement may underestimate BP levels and hypertension detection rate. A study showed that using BP from higher instead of lower reading arms reclassified 12% of people over thresholds used to diagnose hypertension. For accurate diagnosis and management of hypertension bilateral arm BP measurement should be measured [22].
Limitation
This study was performed in the post-stroke patients with hemiparesis in rehabilitation period, thus, the values may be not exactly similar for the acute stroke patients, because the muscle tone of the paretic arm may vary with the acute or chronic phases, which may impact the BP measurement. Previously, Dewar et al. found that a flaccid arm was associated with a lower reading as the hypotonic muscle and easier occlusion of the brachial artery [8]. Secondly, no imaging of the arm and leg artery was collected to confirm their artery disease in this study. But these limitations did not influence our conclusion.