Serdar Demirel

The effect of eversion and conventional-patch technique in carotid surgery on postoperative hypertension

OBJECTIVE Postcarotid endarterectomy hypertension (HTN) is associated with neurological and cardiac complications. The purpose of this study was to assess the influence of eversion carotid endarterectomy (E-CEA) and conventional carotid endarterectomy (C-CEA) on postoperative blood pressure in the first 4 days after surgery. METHODS Two hundred seventy-six consecutive CEAs that were performed between February 2008 and September 2009 were reviewed retrospectively with a computerized registry. After exclusion of patients with severe stroke (modified Rankin Scale of 3-5), prior contralateral and ipsilateral carotid surgery and more than 70% stenosis of the contralateral carotid artery, 201 cases remained (E-CEA group: n = 100 vs C-CEA group: n = 101) for analysis. Results in terms of systolic blood pressure, use of intravenous and oral vasodilators, alterations of the existing antihypertensive medications, and perioperative complications (neck hematoma, myocardial infarction, stroke, and death) were compared. RESULTS Groups were similar with regard to age, sex, and cardiovascular risk factors except for a higher incidence of nicotine use (59% vs 43%; P = .02) in the C-CEA group. Patients in the C-CEA group had a significantly higher percentage of symptomatic carotid artery stenosis (54% vs 23%, respectively; P < .0001). Despite a lower preoperative (baseline) mean systolic blood pressure (130 mm Hg vs 135 mm Hg; P = .02) patients in the E-CEA group had a significantly higher mean systolic blood pressure in the postoperative course up to the day 4 after surgery (134 mm Hg vs 126 mm Hg; P < .0001) and required more frequent intravenous (28% vs 9.9%; P = .001) and oral vasodilators (54% vs 27.7%; P = .0002) compared to those in the C-CEA group. Two-thirds (14 of 21 = 66%) of patients in the E-CEA group with preoperative high blood pressure (systolic blood pressure ≥140 mm Hg and diastolic pressure ≥90 mm Hg) required vasodilators and only one-third (11 of 33 = 33%) in the C-CEA group (P = .03). Atropine use due to bradycardia was necessary after 8 cases (8%) in the C-CEA group and only after 1 case (1%) in the E-CEA group (P = .03). Furthermore, the dosage of existing antihypertensive medications was increased and/or additional medications were prescribed twofold more in the E-CEA group (33% vs 17%; P = .009). No statistically significant difference was noted in the perioperative complication rate. CONCLUSION It is concluded that E-CEA is associated with significantly higher postoperative blood pressure that persists for at least 4 days after surgery. Patients with inadequate preoperative high blood pressure control are particularly at risk after E-CEA.

Multicenter Experience on Eversion Versus Conventional Carotid Endarterectomy in Symptomatic Carotid Artery Stenosis Observations From the Stent-Protected Angioplasty versus Carotid Endarterectomy (SPACE-1) Trial

Background and Purpose— Carotid endarterectomy (CEA) is beneficial in patients with symptomatic carotid artery stenosis. However, randomized trials have not provided evidence concerning the optimal CEA technique, conventional or eversion. Methods— The outcome of 563 patients within the surgical randomization arm of the Stent-Protected Angioplasty versus Carotid Endarterectomy in Symptomatic Patients (SPACE-1) trial was analyzed by surgical technique subgroups: eversion endarterectomy versus conventional endarterectomy with patch angioplasty. The primary end point was ipsilateral stroke or death within 30 days after surgery. Secondary outcome events included perioperative adverse events and the 2-year risk of restenosis, stroke, and death. Results— Both groups were similar in terms of demographic and other baseline clinical variables. Shunt frequency was higher in the conventional CEA group (65% versus 17%; P<0.0001). The risk of ipsilateral stroke or death within 30 days after surgery was significantly greater with eversion CEA (9% versus 3%; P=0.005). There were no statistically significant differences in the rate of perioperative secondary outcome events with the exception of a significantly higher risk of intraoperative ipsilateral stroke rate in the eversion CEA group (4% versus 0.3%; P=0.0035). The 2-year risk of ipsilateral stroke occurring after 30 days was significantly higher in the conventional CEA group (2.9% versus 0%; P=0.017). Conclusions— In patients with symptomatic carotid artery stenosis, conventional CEA appears to be associated with better periprocedural neurological outcome than eversion CEA. Eversion CEA, however, may be more effective for long-term prevention of ipsilateral stroke. These findings should be interpreted with caution noting the limitations of the post hoc, nonrandomized nature of the analysis.

Dynamic Contrast-enhanced Ultrasound for Assessment of Skeletal Muscle Microcirculation in Peripheral Arterial Disease

Objective:This feasibility study was performed to assess whether dynamic contrast-enhanced ultrasound (CEUS) and transient arterial occlusion are able to detect alterations in the microvascular perfusion and arterial perfusion reserve in patients suffering from peripheral arterial disease (PAD) in comparison with healthy volunteers. Materials and Methods:Twenty patients with PAD, Rutherford classification grade I, category III (mean age, 64 years; mean height, 173 cm; mean weight, 81.8 kg), and 20 volunteers (mean age, 50 years; mean height, 174 cm; mean weight, 77.8 kg) participated in the study. Low-mechanical index CEUS (7 MHz; MI, 0.28) was performed to the dominant lower leg after start of a continuous automatic intravenous injection of 4.8 mL suspension with microbubbles containing sulfur hexafluoride (SonoVue) within 5 minutes. Perfusion of the calf muscle was monitored by CEUS before, during, and after release of arterial occlusion at the thigh level lasting for 60 seconds. Several parameters, especially the time to maximum enhancement after release of occlusion (tmax), the maximum enhancement after release of occlusion (maxenh), the total vascular response after release of occlusion (AUCpost), and the resulting slope (m2) to maximum enhancement were calculated. Results:After release of the occlusion, a significantly delayed increase of the CEUS signal to maxenh was observed in the patients with PAD (32 ± 17 seconds) compared with volunteers (17 ± 8 seconds, P = 0.0009). maxenh was 66.5 ± 36.6 (∼mL) in PAD versus 135.6 ± 75.1 (∼mL) in volunteers (P = 0.0016). AUCpost was 3016.5 ± 1825.8 (∼mL·s) in PAD versus 5906.4 ± 3173.1 (∼mL·s) in volunteers (P = 0.0013), and m2 was significantly lower in PAD (3.8 ± 5.2 vs. 14.8 ± 9.7 [∼mL/s], P = 0.0001). Conclusions:Microvascular perfusion deficits and reduced arterial perfusion reserve in patients with PAD are clearly detectable with dynamic CEUS after transient arterial occlusion.

Eversion Carotid Endarterectomy is Associated with Decreased Baroreceptor Sensitivity Compared to the Conventional Technique

OBJECTIVE Impairment of baroreceptor sensitivity (BRS) has been shown to be associated with blood pressure instability after carotid endarterectomy (CEA). The aim of this study was to determine whether there is a difference in postoperative BRS changes following eversion CEA (E-CEA) and conventional CEA (C-CEA). METHODS Sixty-four patients undergoing E-CEA (n = 37) and C-CEA (n = 27) were prospectively studied. Non-invasive measurements of mean arterial pressure (MAP), cardiac output (CO) and total peripheral resistance (TPR) were perioperatively obtained over three 10-min periods. Baroreflex gain was calculated as the sequential cross-correlation between heart rate and beat-to-beat systolic blood pressure. RESULTS Compared with changes observed after C-CEA, E-CEA was associated with an increase in systolic pressure (SP) (P = 0.01), diastolic pressure (DP) (P = 0.008), MAP (P = 0.002) and heart rate (HR) (P = 0.03) on postoperative day 1 (POD-1). BRS decreased after E-CEA from 6.33 to 4.71 ms mmHg(-1) on POD-1 (P = 0.001) and to 5.26 ms mmHg(-1) on POD-3 (P = 0.0004). By contrast, BRS increased after C-CEA from 4.59 to 6.13 ms mmHg(-1) on POD-1 (P = 0.002) and to 6.27 ms mmHg(-1) on POD-3 (P < 0.0001). CONCLUSION E-CEA and C-CEA have different effects on BRS. This is associated with an altered haemodynamic behaviour after E-CEA and C-CEA, respectively. These findings are likely the result of carotid sinus nerve interruption during E-CEA and preservation with C-CEA.

Assessment of skeletal muscle microcirculation in type 2 diabetes mellitus using dynamic contrast-enhanced ultrasound: a pilot study.

Purpose: To investigate muscular micro-perfusion by employing dynamic contrast-enhanced ultrasound (CEUS) and performing transient arterial occlusion in patients with type 2 diabetes mellitus (DM-2). Methods: Twenty DM-2 patients (mean age, 58 ± 8.6 years; duration of diabetes, 15.4 ± 12.1 years) and 20 healthy volunteers (mean age, 54 ± 5.4 years) participated. CEUS was applied to the calf, while 4.8 mL of SonoVue® was injected intravenously. At the thigh level, arterial occlusion (60 s) was performed. CEUS parameters (tmax, max, AUCpost and m) were evaluated and Pearson-product-moment correlation coefficients were computed. Results: A moderate negative correlation of HbA1c and max was established (−0.53). Max in patients with DM-2 >10 years was 79.89 ± 37.4. Max in patients with DM-2 duration <10 years was 137.62 ± 71.72 (p = 0.04). AUCpost in patients with DM-2 duration >10 years was 3924.01 ± 1630.52. AUCpost in patients with DM-2 duration <10 years was 6453.59 ± 3206.23 (p = 0.04). Conclusion: Patients with long history of DM-2 present with impaired muscular perfusion. CEUS and transient arterial occlusion may provide appropriate methods for semi-quantitative evaluation of muscular micro-perfusion in patients with DM-2.

Changes in baroreceptor sensitivity after eversion carotid endarterectomy

OBJECTIVE Posteversion carotid endarterectomy hypertension has been suggested to be associated with impaired baroreceptor sensitivity (BRS), which has been identified as a factor of prognostic relevance in patients with cardiovascular disease. The aim of this prospective single-center nonrandomized study was to describe the changes of BRS in the early postoperative period after eversion carotid endarterectomy (E-CEA). METHODS Spontaneous BRS and hemodynamic parameters such as blood pressure (BP), heart rate (HR), cardiac output (CO), and total peripheral resistance (TPR) were evaluated preoperatively as well as postoperatively after 1 and 3 days using a noninvasive sequential cross-correlation method. Additionally, any modification in vasoactive medication due to BP derangement in the postoperative period was noted. Due to non-normal distribution of BRS, HR, and TPR samples, all measured values were expressed as medians with interquartile range (IQR), and a nonparametric test (Friedman) was performed. After adjustment for multiple testing, differences were considered statistically significant when the two-tailed P value was less than .0036. RESULTS Thirty-five patients (mean age, 71 years) with symptomatic or asymptomatic internal carotid artery stenosis were included. The BRS significantly decreased to a lower level 24 hours after surgery (4.71 ms/mm Hg [3.02-6.1]) than preoperatively (5.95 ms/mm Hg [4.68-10.86]; P < .0001), resulting in a within-patient difference of -2.46 ms/mm Hg (95% confidence interval [CI], -8.38 - -1.52). This difference (95% CI, [- 1.58 (-8.24 - -0.80)]) persisted at the 72-hour measurements (5.63 ms/mm Hg [3.23-7.69]; P = .0005). The HR, reflecting the sympathetic activity, increased 24 hours after the operation (69 bpm [61.3-77.7]) compared with preoperative values (63 bpm [57.9-73.2]; P = .005) (within-patient difference [95% CI] 3.7 [1.5-8.5]), and this increase reached significance at 72 hours (69 bpm [65.4-77.5]; P = .001) (within-patient difference [95% CI] 5.5 [2.3-8.8]). Values of systolic pressure, diastolic pressure, mean arterial pressure, CO, and TPR were not significantly different between pre- and postoperative measurements. Overall, 23 (66%) patients developed significant postoperative hypertension requiring aggressive management with additional medications. CONCLUSIONS E-CEA might have a decreasing influence on BRS, leading to increased sympathetic activity. Investigations of the longer-term effects of impaired BRS are warranted. These findings should be interpreted with caution, noting the limitation of an absent control group.

Dynamic contrast-enhanced ultrasound and transient arterial occlusion for quantification of arterial perfusion reserve in peripheral arterial disease

OBJECTIVE To quantify muscular micro-perfusion and arterial perfusion reserve in peripheral arterial disease (PAD) with dynamic contrast-enhanced ultrasound (CEUS) and transient arterial occlusion. MATERIALS AND METHODS This study had local institutional review board approval and written informed consent was obtained from all subjects. We examined the dominant lower leg of 40 PAD Fontaine stage IIb patients (mean age, 65 years) and 40 healthy volunteers (mean age, 54 years) with CEUS (7 MHz; MI, 0.28) during continuous intravenous infusion of 4.8 mL microbubbles. Transient arterial occlusion at mid-thigh level simulated physical exercise. With time-CEUS-intensity curves obtained from regions of interest within calf muscles, we derived the maximum CEUS signal after occlusion (max) and its time (tmax), slope to maximum (m), vascular response after occlusion (AUC(post)), and analysed accuracy, receiver operating characteristic (ROC) curves, and correlations with ankle-brachial index (ABI) and walking distance. RESULTS All parameters differed in PAD and volunteers (p<0.014). In PAD, tmax was delayed (31.2±13.6 vs. 16.7±8.5 s, p<0.0001) and negatively correlated with ankle-brachial-index (r=-0.65). m was decreased in PAD (4.3±4.6 mL/s vs. 13.1±8.4 mL/s, p<0.0001) and had highest diagnostic accuracy (sensitivity/specificity, 75%/93%) for detection of diminished muscular micro-perfusion in PAD (cut-off value, m<5∼mL/s). Discriminant analysis and ROC curves revealed m, and AUC(post) as optimal parameter combination for diagnosing PAD and therefore impaired arterial perfusion reserve. CONCLUSIONS Dynamic CEUS with transient arterial occlusion quantifies muscular micro-perfusion and arterial perfusion reserve. The technique is accurate to diagnose PAD.

Comparison of renin and catecholamine release in patients undergoing eversion or conventional carotid endarterectomy

OBJECTIVE The two techniques for carotid endarterectomy (CEA)--conventional (C-CEA) and eversion (E-CEA)--have different effects on blood pressure. This study compared sympathetic activity after C-CEA and E-CEA, as measured by renin and catecholamine levels. METHODS E-CEA (n = 40) and C-CEA (n = 34) were performed in 74 patients with high-grade carotid stenosis. The choice of technique was made at the discretion of the operating surgeon. All patients received clonidine (150 μg) preoperatively. Regional anesthesia was used. The carotid sinus nerve was transected during E-CEA and preserved during C-CEA. Renin, metanephrine, and normetanephrine levels were measured preoperatively and at 24 and 48 hours postoperatively. RESULTS Compared with baseline, levels of renin, metanephrine, and normetanephrine decreased at 24 and 48 hours after C-CEA (P < .0001). After E-CEA, however, renin and normetanephrine levels were unchanged at 24 hours, and metanephrine levels were increased (P < .0001). At 48 hours, levels of renin (P = .04), metanephrine (P < .0001), and normetanephrine (P = .02) were increased. Compared with C-CEA, E-CEA was associated with significantly increased sympathetic activity at 24 and 48 hours (P < .0001). Although the use of vasodilators for postoperative hypertension did not differ in the postanesthesia care unit (E-CEA 35% vs C-CEA 18%, P = .12), vasodilator use on the ward was more frequent after E-CEA (60% vs 32%, P = .02). CONCLUSIONS E-CEA appears to be associated with greater postoperative sympathetic activity and vasodilator requirements than C-CEA, findings likely related to sacrifice of the carotid sinus nerve during E-CEA but not C-CEA.

Systematic review and meta-analysis of postcarotid endarterectomy hypertension after eversion versus conventional carotid endarterectomy

Objective: Blood pressure (BP) instability after carotid endarterectomy (CEA) is a risk factor for cerebrovascular and cardiovascular complications. The role of the operative technique in the development of post‐CEA hemodynamic instability is unclear. The primary goal of this study was to systematically review the literature to determine whether hypertension in the early postoperative period is dependent on the surgical technique used. Methods: We searched MEDLINE, Cochrane CENTRAL, and Web of Science through June 2016 without restrictions to language or starting date. The interventions of interest were eversion CEA (E‐CEA) compared with conventional CEA (C‐CEA) with or without patch plasty. The primary outcome of interest was the incidence of postoperative need for vasodilator therapy because of hypertension in the early postoperative period, the duration of which was predefined in the individual studies. Secondary outcomes were the intergroup mean difference of the mean within‐group changes of postoperative (24 hours) to baseline systolic BP, the incidence of hypotension requiring vasopressor therapy, and the rate of complications. The odds ratio (OR) of each binary outcome was pooled across studies with its 95% confidence interval (CI). For meta‐analysis of continuous outcomes, the weighted mean differences with the corresponding 95% CIs were pooled. Strength of evidence of the outcomes was judged according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines. Results: We identified six studies, of which four were nonrandomized prospective and two retrospective with low to moderate risk of bias. In addition, results of a post hoc analyses of a randomized controlled trial were included, resulting in a total number of seven included studies. Duration of the postoperative study period ranged from 1 to 6 days. The meta‐analysis of all studies regarding the primary outcome demonstrated increased rates of post‐CEA hypertension after E‐CEA (pooled OR, 2.75; 95% CI, 1.82–4.16; I2 = 49.9%). The pooled weighted intergroup mean difference between the E‐CEA and C‐CEA effects on postoperative systolic BP was +12.92 mm Hg (95% CI, 8.06–17.78; I2 = 93.6%; P < .0001). Hypotension was significantly higher in the C‐CEA group (pooled OR, 11.37; 95% CI, 1.95–66.46; I2 = 0%). There was no difference in postoperative complications including myocardial infarction, stroke, neck hematoma, or death. Strength of evidence contributing to the primary outcome as well as the hypotension outcome was graded as moderate and that contributing to the other secondary outcomes was graded as very low. Conclusions: E‐CEA increases the risk for post‐CEA hypertension, whereas C‐CEA is more often associated with hypotension, Careful BP monitoring at least in the early postoperative period after CEA is mandatory, especially when the eversion technique is used.

Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics – a pilot study

Purpose: To compare postoperative morphological and rheological conditions after eversion carotid endarterectomy versus conventional carotid endarterectomy using computational fluid dynamics. Basic methods: Hemodynamic metrics (velocity, wall shear stress, time-averaged wall shear stress and temporal gradient wall shear stress) in the carotid arteries were simulated in one patient after conventional carotid endarterectomy and one patient after eversion carotid endarterectomy by computational fluid dynamics analysis based on patient specific data. Principal findings: Systolic peak of the eversion carotid endarterectomy model showed a gradually decreased pressure along the stream path, the conventional carotid endarterectomy model revealed high pressure (about 180 Pa) at the carotid bulb. Regions of low wall shear stress in the conventional carotid endarterectomy model were much larger than that in the eversion carotid endarterectomy model and with lower time-averaged wall shear stress values (conventional carotid endarterectomy: 0.03–5.46 Pa vs. eversion carotid endarterectomy: 0.12–5.22 Pa). Conclusions: Computational fluid dynamics after conventional carotid endarterectomy and eversion carotid endarterectomy disclosed differences in hemodynamic patterns. Larger studies are necessary to assess whether these differences are consistent and might explain different rates of restenosis in both techniques.