Transcranial colour duplex and central aortic pressure measurements in the management of cerebral arteriovenous malformations: a pilot study using non-invasive measures

Background: Following removal of an arteriovenous malformation of the brain (bAVM) the redistribution of blood can impose several clinically challenging issues including intracranial haemorrhage and arteriovenous capillary hypertensive syndrome. The underlying mechanism of such complications remains controversial, although control of blood pressure has been recognised as an integral component in haemorrhage prevention. Serial daily non-invasive monitoring for patients in this instance would be beneficial in improving management. Transcranial colour duplex (TCD) is a potential technique for providing pressure measurements and real-time, dynamic, haemodynamic spectra. Aim: To establish whether blood outflow velocity in the middle cerebral vein (MCV) can be quantified in the days following bAVM resection and whether values differ from other types of intracranial surgery. Methods: Blood pressure and TCD of 13 patients (aged 46±19 y, 7 female) having bAVMs resected and 7 patients having other intracranial surgeries (control group, aged 48±15 y, 6 female) were studied for days 1 to 3 following surgery. Ultrasound via the transtemporal window was used to obtain diameter, as well as peak and end-diastolic velocity of the MCV. Brachial blood pressure was also obtained using an automatic oscillometric blood pressure monitor. Results: Systolic (bAVM 96±2 mmHg, control 89±10 mmHg; P=0.68) and diastolic blood pressure (bAVM 55±2 mmHg, control 48±7 mmHg; P=0.92) did not differ between the groups. MCV peak systolic velocity was greater in the bAVM group (34±20 cm/s, controls 20±9 cm/s; P=0.049). The control group had peak systolic velocities ranging from 9 to 32 cm/s. Peak systolic velocity in the bAVM group varied from 9 to 98 cm/s. End diastolic velocity (bAVM 13±11 cm/s, control 13±6 cm/s; P=0.89) and diameters (bAVM 37±19 mm, control 26±7 mm; P=0.16) did not differ between the groups. Two of the bAVM patients that had sustained high MCV peak velocities had a post-operative haemorrhage. Conclusions: Unusually elevated blood flow velocities and diameters were observed in the MCV of patients following bAVM resection. Findings on this small data set provide insight into plausible vessel remodelling and elucidate a post-operative time frame when vessels may have impaired autoregulation of cerebral blood flow.