Warning criteria for MEP monitoring during carotid endarterectomy: a retrospective study of 571 patients.

Monitoring of transcranial electrical motor evoked potentials (tcMEP) during carotid endarterectomy (CEA) has been shown to effectively detect intraoperative cerebral ischemia. The unique purpose of this study was to evaluate changes of MEP amplitude (AMP), area under the curve (AUC) and signal morphology (MOR) as additional MEP warning criteria for clamping-associated ischemia during CEA. Therefore, the primary outcome was the number of MEP alerts (AMP, AUC and MOR) in the patients without postoperative motor deficit (false positives). We retrospectively reviewed data from 571 patients who received CEA under general anesthesia. Monitoring of somatosensory evoked potentials (SSEP) and tcMEP was performed in all cases (all-or-none MEP warning criteria). The percentages of false positives (primary parameter) of AMP, AUC and MOR were evaluated according to the postoperative motor outcome. In the cohort of 562 patients, we found significant SSEP/MEP changes in 56 patients (9.96%). In 44 cases (7.83%) a shunt was inserted. Nine patients (1.57%) were excluded due to MEP recording failure. False positives were registered for AMP, AUC and MOR changes in 121 (24.01%), 148 (29.36%) and 165 (32.74%) patients, respectively. In combination of AMP/AUC and AMP/AUC/MOR false positives were found in 9.52% and 9.33% of the patients. This study is the first to evaluate the correctness of the MEP warning criteria AMP, AUC and MOR with regard to false positive monitoring results in the context of CEA. All additional MEP warning criteria investigated produced an unacceptably high number of false positives and therefore may not be useful in carotid surgery for adequate detection of clamping-associated ischemia.

Blood pressure after blinded, randomized withdrawal, and resumption of baroreceptor-activating therapy.

BACKGROUND: Baroreceptor-activating therapy (BAT) has been shown to control resistant hypertension in one sham-controlled and further observational studies. Incremental but significant reincrease of blood pressure (BP) have been described after open-label temporary withdrawal of such therapy. METHOD: Our study in 16 randomized patients investigated the course of automated office, ambulatory, and home BP in a randomized, controlled cross-over design. RESULTS: After 4 weeks of blinded and randomized withdrawal in hypertension-controlled long-term carriers of BAT (2.67 ±â€Š1.3 years, 145/104 mmHg), the primary end point of 35 mmHg difference, similar to initial BP drop after BAT initiation, was not reached in any patient. Ambulatory BP rose significantly during BAT off by 10/8 ±â€Š4/3 mmHg (3.13/2.10, P = 0.007/0.002) and automated office BP by 10/4 ±â€Š2/1 (4.17/0.58, P = 0.005/0.03) at 4 weeks after BAT on while mean home BP did not change significantly by 2/2 ±â€Š3/2 mmHg (-5.9/-3.5, P = 0.6/0.5). CONCLUSION: Our data in a limited study population show, that BP rise after temporary BAT withdrawal is significant but does not reach a magnitude comparable with the initial drop after de novo implantation. Such results points to preserved hypertension control after electrical BAT withdrawal and deserves further pathophysiological and clinical clarification.

Baroreflex activation therapy in patients with end-stage renal failure: proof of concept.

BACKGROUND: Resistant arterial hypertension and chronic kidney disease (CKD) are interlinked via sympathetic overactivity. Baroreflex activation therapy (BAT) is a well tolerated therapy, which has been shown to reduce BP in patients with resistant hypertension. The effects of BAT in patients with resistant hypertension and end stage renal disease have not been reported. METHOD AND RESULTS: We retrospectively analyzed procedural effectiveness and safety in seven CKD stage 5D patients with resistant hypertension who underwent BAT. One year after activation, office SBP decreased significantly from 194 ±â€Š28 to 137 ±â€Š16 mmHg (P < 0.01). Ambulatory SBP showed a trend to be decreased from 167 ±â€Š30 to 137 ±â€Š24 mmHg (P = 0.17), whereas the median number of prescribed antihypertensive classes decreased from 5 (4-9) to 3 (1-4) (P = 0.01). Intraoperative drop of SBP was -34.3 ±â€Š34.4 mmHg (P = 0.04). With respect to adverse events there were minor side-effects (mainly paresthesia and dysphagia) reported in our patients, which occurred according to treatment intensity and modality. CONCLUSION: BAT is an effective and well tolerated intervention to reduce BP in patients suffering from end-stage renal disease and resistant hypertension. Therefore, BAT might contribute to a reduction of cardiovascular events in those high-risk patients.