Post-operative endothelial dysfunction assessment using laser Doppler perfusion measurement in cardiac surgery patients

Assessment of microcirculatory alteration by a vascular occlusion test using near-infrared spectroscopy in pediatric cardiac surgery: effect of cardiopulmonary bypass

OBJECTIVES

Cardiopulmonary bypass cause microcirculatory alterations. Near infrared spectroscopic measurement of tissue oxygen saturation and vascular occlusion test are novel technologies for assessing the microcirculatory function of peripheral tissue specifically in patients undergoing cardiac surgery with cardiopulmonary bypass.Our study aimed to evaluate dynamic microcirculatory function using the vascular occlusion testing during cardiac surgery in pediatric patients.

METHODS

120 pediatric patients were scheduled. Children had continuous regional oxygen saturation monitoring using near infrared spectroscopy and vascular occlusion test. Vascular occlusion test was performed five times; before induction (T1), after induction (T2), then during cardiopulmonary bypass with full flow (T3), after the termination of CPB (T4) and after sternum closure (T5).

RESULTS

Basal value was the lowest at T3 and this value was significantly different among measurements (p < 0,01).Values for maximum and minimum tissue oxygen saturation were the lowest at T3 (83,4 and 52,9%).The occlusion slope varied significantly among measurements (p < 0,01).Reperfusion slopes were significantly different among measurements (p < 0,01) with a further progressive decrease in reperfusion slope with duration of cardiopulmonary bypass.

CONCLUSION

Microcirculatory function can assessed using VOT with forearm Near-infrared spectroscopy derived variables during cardiopulmonary bypass in pediatric cardiac surgery. Noninvasive assessment of microcirculatory perfusion during cardiopulmonary bypass can further help evaluate and improve circulatory support techniques.

TRIAL REGISTRATION

The research Project was registered at ClinicalTrials.gov (NCT06191913).

Preoperative endothelial dysfunction for the prediction of acute kidney injury after cardiac surgery using cardiopulmonary bypass: a pilot study based on a second analysis of the MONS study

BACKGROUND

Up to 42% of patients develop acute kidney injury (AKI) after cardiac surgery. The aim of this study was to describe the relationship between preoperative microcirculatory function and postoperative AKI after cardiac surgery using cardiopulmonary bypass (CPB).

METHODS

The prospective observational cohort MONS enrolled 60 patients scheduled for valvular (n = 30, 50%) or coronary (n = 30, 50%) surgery using CPB. Preoperative microcirculation was assessed during preoperative consultation from January 2019 to April 2019 at the University Hospital of Angers, France, using endothelium-dependent and endothelium-independent reactivity tests on the forearm (iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP), respectively). Skin blood flow was measured by laser speckle contrast imaging. The primary endpoint was the occurrence of AKI according to the KDIGO classification during the hospital stay.

RESULTS

Forty-three (71.7%) patients developed AKI during the in-hospital follow-up, and 15 (25%) were classified as KDIGO stage 1, 20 (33%) KDIGO stage 2, and 8 (13%) KDIGO stage 3. Regarding preoperative microcirculation, a higher peak amplitude of vasodilation in response to iontophoresis of ACh was found in patients with postoperative occurrence of AKI (35 [20-49] vs 23 [9-44] LSPU, p = 0.04). Iontophoresis of SNP was not significantly different according to AKI occurrence (34 [22-49] vs 36 [20-50] LSPU, p = 0.95). In a multivariable model, the preoperative peak amplitude at iontophoresis of ACh was independently associated with postoperative AKI (OR 1.045 [1.001-1.092], p = 0.045).

CONCLUSIONS

The preoperative peak amplitude of endothelium-dependent vasodilation is independently associated with the postoperative occurrence of AKI.

TRIAL REGISTRATION

Clinical-Trials.gov, NCT03631797. Registered 15 August 2018, https://clinicaltrials.gov/ct2/show/NCT03631797.

Endothelial Damage and Muscle Wasting in Cardiac Surgery Patients

This is a post-hoc analysis to assess the effect of anesthesia, surgical trauma, and extracorporeal circuit on endothelial integrity, microvascular permeability, and extracellular fluid balance, as well as on skeletal muscle catabolism, in patients undergoing elective cardiac surgery. We included 127 well-nourished patients undergoing “on-pump” elective cardiac surgery. One day prior to surgery (D0) and again on postoperative day 7 (POD7), body mass index, body composition assessment, hand-grip strength (HGS), and mid-upper arm muscle circumference (MAMC) were measured. Patients were assigned to early recovery (ER) and late recovery (LR) groups, depending on the duration of ICU stay (cut-off 48 hours). The magnitude of change (Δ) in all parameters studied was assessed in ER versus LR groups, regarding (i) epithelial tissue dysfunction (Δ-Extra-Cellular Water percentage (Δ-ECW%), Δ-Phase Angle (Δ-PhA)), (ii) skeletal muscle mass catabolism (Δ-Skeletal muscle mass reduction%, Δ-Hand Grip Strength (Δ-HGS) and Δ-Mid Upper-Arm Muscle Circumference (Δ-MAMC)). Baseline measurements were similar in both groups. A significant difference was observed in all Δ-parameters studied (Δ-ECW%, Δ-PhA and muscle catabolism, Δ-HGS, Δ-MAMC), the worse results being correlated to the LR group. The results raise the issue that patients with early recovery may silently have pathological conditions, continuing even on the day of discharge - further research should be planned.

Improved Retinal Microcirculation After Cardiac Surgery in Patients With Congenital Heart Disease

Background: Microcirculatory changes in congenital heart disease (CHD) patients undergoing cardiac surgery are not fully understood. We aimed to investigate the changes of retinal microcirculation in CHD patients after cardiac surgery by optical coherence tomography angiography (OCTA) and explore the association between retinal microcirculation and surgical outcome.

Methods: This prospective observational study consisted of 71 CHD patients aged ≥6 years undergoing cardiac surgery including 19 cyanotic CHD (CCHD) and 52 acyanotic CHD (ACHD). Optical coherence tomography angiography (OCTA) was used to measure vessel density (VD) and capillary density (CD) of radial peripapillary capillary (RPC) and peripapillary, VD of superficial capillary plexus (SCP) and deep capillary plexus (DCP), thickness of retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) preoperatively and 1 month postoperatively. Transthoracic echocardiography was conducted to measure macrocirculation.

Results: In CCHD patients, VD and CD of RPC and peripapillary increased postoperatively (all P < 0.05). In ACHD patients, VD of peripapillary, CD of RPC and peripapillary, and RNFL thickness increased postoperatively (all P < 0.05). VD of SCP and DCP, and GCC thickness did not change significantly in CHD patients after surgery. Lower preoperative retinal microvascular density was associated with longer cardiopulmonary bypass (CPB) time and postoperative length of stay (PLOS). No correlation was found between microcirculatory and macrohemodynamic parameters (all P > 0.05).

Conclusions: Improved retinal microcirculation was observed after congenital cardiac surgery and impaired preoperative retinal microvasculature was associated with prolonged CPB time and PLOS, which might provide potential information about the outcome of congenital cardiac surgery.

Preoperative endothelial dysfunction in cutaneous microcirculation is associated with postoperative organ injury after cardiac surgery using extracorporeal circulation: a prospective cohort study

Background

Cardiac surgery is known to induce acute endothelial dysfunction, which may be central to the pathophysiology of postoperative complications. Preoperative endothelial dysfunction could also be implicated in the pathophysiology of postoperative complications after cardiac surgery. However, the relationship between preoperative endothelial function and postoperative outcomes remains unknown. The primary objective was to describe the relationship between a preoperative microcirculatory dysfunction identified by iontophoresis of acetylcholine (ACh), and postoperative organ injury in patients scheduled for cardiac surgery using cardiopulmonary bypass (CPB).

Methods

Sixty patients undergoing elective cardiac surgery using CPB were included in the analysis of a prospective, observational, single-center cohort study conducted from January to April 2019. Preoperative microcirculation was assessed with reactivity tests on the forearm (iontophoresis of ACh and nitroprusside). Skin blood flow was measured by laser speckle contrast imaging. Postoperative organ injury, the primary outcome, was defined as a Sequential Organ Failure Assessment score (SOFA) 48 h after surgery greater than 3.

Results

Organ injury at 48 h occurred in 29 cases (48.3%). Patients with postoperative organ injury (SOFA score > 3 at 48 h) had a longer time to reach the peak of preoperative iontophoresis of acetylcholine (133 s [104–156] vs 98 s [76–139] than patients without, P = 0.016), whereas endothelium-independent vasodilation to nitroprusside was similar in both groups. Beyond the proposed threshold of 105 s for time to reach the peak of preoperative endothelium-dependent vasodilation, three times more patients presented organ dysfunction at 48 h (76% vs 24% below or equal 105 s). In multivariable model, the time to reach the peak during iontophoresis of acetylcholine was an independent predictor of postoperative organ injury (odds ratio = 4.81, 95% confidence interval [1.16–19.94]; P = 0.030).

Conclusions

Patients who postoperatively developed organ injury (SOFA score > 3 at 48 h) had preoperatively a longer time to reach the peak of endothelium-dependent vasodilation.

Trial registration Clinical-Trials.gov, NCT03631797. Registered 15 August 2018, https://clinicaltrials.gov/ct2/show/NCT03631797

Relationship between endothelial function and vascular stiffness on lower limit of cerebral autoregulation in patients undergoing cardiovascular surgery

Hemodynamic management based on cerebral autoregulation range is a possible strategy for preserving major organ perfusion during cardiovascular surgery. The purpose of this study was to evaluate the relation of vascular properties with lower limit of cerebral autoregulation (LLA). LLA was monitored in 66 patients undergoing cardiovascular surgery using near-infrared spectroscopy. To determine the clinical importance of LLA monitoring, association of blood pressure excursions below LLA and acute kidney injury (AKI) was evaluated. Flow-mediated dilation (FMD) and pulse wave velocity (PWV) were measured for the evaluation of endothelial function and aortic stiffness. Variables associated with LLA were evaluated. Excluding patients on hemodialysis, there were 15 patients (25.9%) who developed AKI. Blood pressure excursions below LLA were higher in patients who developed AKI (4.55 mm Hg × hr vs. 1.23 mm Hg × hr, P = .017). In the univariate analysis, prevalence of ischemic heart disease (No IHD: 53 ± 13.0 mm Hg vs. IHD: 60.0 ± 13.6 mm Hg, P = .056) and FMD (r = -0.42, 95% CI -0.61 to -0.19, P < .001) were associated with LLA before cardiopulmonary bypass (CPB). During CPB, calcium channel blocker (No Ca blocker: 42 ± 10.6 mm Hg vs. Ca blocker: 49 ± 14.3 mm Hg, P = .033), diabetes (no DM: 44 ± 13.2 mm Hg vs. DM: 55 ± 10.0 mm Hg, P = .024), FMD (r = -0.32, 95% CI -0.55 to -0.05, P = .021), and PWV (r = 0.28, 95% CI 0.012 to 0.513, P = .041) were associated with LLA. Multivariate analysis showed that FMD was correlated with LLA before CPB (r = -2.19, 95% CI -3.621 to -0.755, P = .003), while PWV was correlated with LLA during CPB (r = 0.01, 95% CI 0.001-0.019, P = .023). Endothelial function and aortic stiffness may be important factors in determining LLA at different phases in cardiovascular surgery.

Endothelial-Dependent Vasomotor Dysfunction in Infants After Cardiopulmonary Bypass

OBJECTIVES

Cardiopulmonary bypass-induced endothelial dysfunction has been inferred by changes in pulmonary vascular resistance, alterations in circulating biomarkers, and postoperative capillary leak. Endothelial-dependent vasomotor dysfunction of the systemic vasculature has never been quantified in this setting. The objective of the present study was to quantify acute effects of cardiopulmonary bypass on endothelial vasomotor control and attempt to correlate these effects with postoperative cytokines, tissue edema, and clinical outcomes in infants.

DESIGN

Single-center prospective observational cohort pilot study.

SETTING

Pediatric cardiac ICU at a tertiary children's hospital.

PATIENTS

Children less than 1 year old requiring cardiopulmonary bypass for repair of a congenital heart lesion.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

Laser Doppler perfusion monitoring was coupled with local iontophoresis of acetylcholine (endothelium-dependent vasodilator) or sodium nitroprusside (endothelium-independent vasodilator) to quantify endothelial-dependent vasomotor function in the cutaneous microcirculation. Measurements were obtained preoperatively, 2-4 hours, and 24 hours after separation from cardiopulmonary bypass. Fifteen patients completed all laser Doppler perfusion monitor (Perimed, Järfälla, Sweden) measurements. Comparing prebypass with 2-4 hours postbypass responses, there was a decrease in both peak perfusion (p = 0.0006) and area under the dose-response curve (p = 0.005) following acetylcholine, but no change in responses to sodium nitroprusside. Twenty-four hours after bypass responsiveness to acetylcholine improved, but typically remained depressed from baseline. Conserved endothelial function was associated with higher urine output during the first 48 postoperative hours (R = 0.43; p = 0.008).

CONCLUSIONS

Cutaneous endothelial dysfunction is present in infants immediately following cardiopulmonary bypass and recovers significantly in some patients within 24 hours postoperatively. Confirmation of an association between persistent endothelial-dependent vasomotor dysfunction and decreased urine output could have important clinical implications. Ongoing research will explore the pattern of endothelial-dependent vasomotor dysfunction after cardiopulmonary bypass and its relationship with biochemical markers of inflammation and clinical outcomes.

Microvascular endothelial dysfunction during cardiopulmonary bypass in surgery for correction of cyanotic and acyanotic congenital heart disease

OBJECTIVE

To evaluate endothelium-dependent microvascular reactivity during cardiopulmonary bypass (CPB) in surgery for the correction of cyanotic and acyanotic congenital heart disease (CHD) in children and infants using laser Doppler perfusion monitoring (LDPM).

METHODS

This cross-sectional observational study included one hundred consecutive acyanotic (AC, n = 61) and cyanotic (C, n = 39) pediatric patients scheduled for cardiac surgery for correction of CHD. The endothelium-dependent microvascular vasodilation of the skin of the forehead was evaluated using a single-point LDPM coupled with local thermal hyperemia (LTH).

RESULTS

LTH induced significant increases in microvascular conductance both in AC and C patients after the induction of anesthesia, during CPB and after weaning from CPB. Nevertheless, the vasodilation induced by LTH was significantly blunted during CPB when compared with values obtained after the induction of anesthesia both in AC and C patients. Microvascular endothelial reactivity nearly normalized after the discontinuation of CPB.

CONCLUSION

The evaluation of systemic microvascular reactivity on the forehead skin of infants and children using LDPM appears to be a valuable tool for optimizing microvascular perfusion during CPB in pediatric cardiac surgery.

Evaluation of microvascular endothelial function and capillary density in patients with infective endocarditis using laser speckle contrast imaging and video-capillaroscopy

OBJECTIVE

To evaluate the systemic microcirculation of patients with infective endocarditis (IE).

METHODS

This is a comparative study of patients with definite IE by the modified Duke criteria admitted to our center for treatment. A reference group of sex- and age-matched healthy volunteers was included. Microvascular flow was evaluated in the forearm using a laser speckle contrast imaging system, for noninvasive measurement of cutaneous microvascular perfusion, in combination with skin iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) to test microvascular reactivity. Microvascular density was evaluated using skin video-capillaroscopy.

RESULTS

We studied 22 patients with IE; 15 were male and seven female. The mean age and standard deviation (SD) were 45.5 ± 17.3 years. Basal skin microvascular conductance was significantly increased in patients with IE, compared with healthy individuals (0.36 ± 0.13 versus 0.21 ± 0.08 APU/mmHg; P < 0.0001). The increase in microvascular conductance induced by ACh in patients was 0.21 ± 0.17 and in the reference group, it was 0.37 ± 0.14 APU/mmHg (P = 0.0012). The increase in microvascular conductance induced by SNP in patients was 0.18 ± 0.14 and it was 0.29 ± 0.15 APU/mmHg (P = 0.0140) in the reference group. The basal mean skin capillary density of patients (135 ± 24 capillaries/mm²) was significantly higher, compared with controls (97 ± 21 capillaries/mm²; P < 0.0001).

CONCLUSIONS

The main findings in the microcirculation of patients with IE were greater basal vasodilation and a reduction of the endothelium-dependent and -independent microvascular reactivity, as well as greater functional skin capillary density compared to healthy individuals.

Near-infrared spectroscopy to assess microvascular dysfunction: A prospective pilot study in cardiac surgery patients

PURPOSE

The diagnosis of microvascular dysfunction remains challenging after cardiac surgery. We hypothesized that peripheral near-infrared spectroscopy (NIRS) monitoring in combination with a vascular occlusion test could reliably assess postoperative microvascular dysfunction in that setting.

MATERIALS AND METHODS

Twenty-two patients undergoing cardiac surgery with cardiopulmonary bypass and 10 healthy volunteers were prospectively investigated. Relevant NIRS parameters (regional tissue oxygen saturation, desaturation, and resaturation rates) were recorded the day before surgery (D-1), at the arrival in the intensive care unit (postoperative day [POD] 0) and on POD 1 and POD 2.

RESULTS

No difference in NIRS parameters was found at baseline between healthy volunteers and cardiac surgical patients. Absolute values of regional tissue oxygen saturation significantly increased at POD 0 and POD 1 when compared with D-1: 78% (75%-81%) and 75% (73%-78%) vs 68% (64%-72%), P < .001. No statistical difference was evidenced within the postoperative period in desaturation and resaturation rates compared with D-1: desaturation rate, 0.11% · s(-1) (0.08-0.14) and 0.15% · s(-1) (0.08-0.22) vs 0.14% · s(-1) (0.10-0.17), P = .233, and resaturation rate, 0.76% · s(-1) (0.41-1.11) and 0.77% · s(-1) (0.53-1.02) vs 0.79% · s(-1) (0.61-0.97), P = .453. The use of postoperative norepinephrine infusion did not change the results.

CONCLUSIONS

Peripheral NIRS monitoring in combination with a vascular occlusion test failed to assess cardiopulmonary bypass-induced microvascular dysfunction.