A New Doppler-Derived Parameter to Quantify Internal Carotid Artery Stenosis: Maximal Systolic Acceleration

Unmasking the hidden culprit: Recurrent syncope in a 62-year-old man linked to severe internal carotid artery stenosis

Syncope, a brief loss of consciousness, has many potential causes, with internal carotid artery (ICA) stenosis being a relatively uncommon but serious one. We present the case of a 62-year-old man from Dhaka, Bangladesh, who experienced recurrent syncope over 6 months, characterized by a brief loss of consciousness, occasional dizziness, and blurred vision. Despite a history of hypertension and hyperlipidemia, initial cardiac and neurogenic investigations were inconclusive. Magnetic resonance angiography revealed 90% stenosis of the right ICA, which was confirmed by digital subtraction angiography. The patient was treated with antiplatelet therapy, statins, and antihypertensives, and underwent carotid artery stenting. His postoperative recovery was uneventful, and he remained symptom-free during follow-up. This case underscores the importance of considering ICA stenosis in patients with recurrent syncope and comorbid vascular disease, particularly in resource-limited settings where timely diagnosis and intervention can prevent serious cerebrovascular complications.

Accuracy of maximal acceleration time of pedal arteries to diagnose critical limb-threatening ischemia

INTRODUCTION

Maximal acceleration time of distal arteries of the foot (ATmax) is correlated to ankle-brachial index (ABI) and toe-brachial index (TBI), and seems very promising in diagnosing severe peripheral artery disease (PAD) and especially critical limb-threatening ischemia (CLTI). Our goal was to confirm the cut-off value of 215 ms to predict a toe pressure (TP) ⩽ 30 mmHg.

METHODS

A 4-month retrospective study was conducted on patients addressed for suspicion of PAD. Demographic data, ABI, TBI, and Doppler ultrasound scanning parameters of the dorsal pedis and lateral plantar arteries (DPA and LPA) were recorded.

RESULTS

A total of 137 patients with 258 lower limbs were included. ATmax was highly correlated to TBI (r = -0.89, p < 0.001). With the cut-off value of 215 ms, ATmax was effective to diagnose TP ⩽ 30 mmHg with a sensitivity of 93% [95% CI 77-99], a specificity of 96% [95% CI 92-98], a positive predictive value of 73% [95% CI 56-86], a negative predictive value of 99% [95% CI 97-100], and an area under the receiver operating characteristics curve of 0.99 [95% CI 0.98-1.00]. ATmax also showed promising results to rule out PAD in healthy patients.

CONCLUSION

ATmax is a reliable diagnostic tool to diagnose low TP and could be a new easily performed hemodynamic criterion for diagnosis of CLTI.

Impaired Dynamic Cerebral Autoregulation as a Predictor for Cerebral Hyperperfusion After Carotid Endarterectomy: A Prospective Observational Study

OBJECTIVE

Cerebral hyperperfusion syndrome (CHS) is a severe complication of carotid endarterectomy (CEA). Because cerebral hyperperfusion (CH) reduces the benefits of CEA, it is important to identify patients at high risk of developing CH. We investigated dynamic cerebral autoregulation (dCA) as a potential predictor of CH after CEA.

METHODS

In a prospective observational study of 90 patients, we defined CH as a ≥100% increase in the transcranial Doppler ultrasound-derived mean flow velocity of the middle cerebral artery compared to baseline, with or without clinical manifestations. We examined dCA in the supine position and during squat-stand maneuvers using the transfer function, analyzing phase, gain, and coherence. Logistic regression analysis and receiver operating characteristic (ROC) curves were used to assess the relationships between variables and outcomes.

RESULTS

Cerebral hyperperfusion (CH) occurred in 18 patients after CEA. The CH group had a lower ipsilateral phase for both body postures than the non-CH group at very low and low frequencies, respectively (both P < 0.01). Postoperative CH was independently associated with the preoperative peak systolic velocity (PSV)sten/PSVdis ratio and the ipsilateral phase in both body postures at a very low frequency. Receiver operating characteristic (ROC) curve analysis showed that the ipsilateral phase had excellent CH predictive accuracy in the supine position and squat-stand maneuvers at a very low frequency (areas under the curve: 0.809 and 0.839, respectively, both P < 0.001; cutoff values: 24.7 and 11.7, respectively).

CONCLUSIONS

The lower ipsilateral phase may serve as a predictor of CH after CEA.

Arterial Blood-Flow Acceleration Time on Doppler Ultrasound Waveforms: What Are We Talking About?

In recent years, the assessment of systolic acceleration in lower-extremity peripheral artery disease (PAD) has been brought back into the spotlight, whatever measure is used: time (in s) or acceleration (in cm.s^-2). Acceleration time (also called systolic rise time) and maximal acceleration are two different but very useful measurements of growing interest in PAD. A background of the historical development, physics rationale, semantics, and methods of measurement, as well as their strengths and weaknesses, are discussed herein. Acceleration time is a powerful tool for predicting significant arterial stenosis or for estimating the overall impact of PAD as it is highly correlated to the ankle or toe pressure indexes. It could even become a new diagnostic criterion for critical limb ischemia. Similarly, maximal systolic acceleration ratios are highly predictive of carotid or renal stenosis. However, the literature lacks reference standards or guidelines for the assessment of such variables, and their measurement techniques seem to differ between authors. We propose herein a semantic and measurement statement order to clarify and help standardize future research.