OC-087 PAIN AND INFLAMMATORY SIGNALLING IN TACKOMESH TRIAL PARTICIPANTS FOLLOWING ELECTIVE LAPAROSCOPIC INCISIONAL HERNIA REPAIR WITH INTRAPERITONEAL ONLAY MESH (IPOM) AND SPIRAL-TACK MESH FIXATION

Background

The aim of this study was to investigate for links between reported pain and inflammation within a sub-cohort of patients undergoing the IPOM plus repair through the measurement of serum/plasma levels of established inflammatory biomarkers in trial participants across 1-year follow up.

Methods

22 patients (12 Protack™ and 10 Reliatack™) within the TACKoMesh randomised controlled trial underwent serial blood sampling as part of their follow up. A panel of pro- and anti-inflammatory biomarkers were assayed using Luminex multiplex assays and ELISAs. Circulating biomarker concentrations were described and compared in the context of clinical and patient reported outcome data that was obtained within the trial.

Results

An increase in the serum concentration of pro- (IL-6 and CRP) and anti- (IL-10) inflammatory biomarkers was seen following IPOM plus repair. Serum IL-6 and CRP were significantly raised compared to baseline at post-operative Days 1, 6 and 30 (p < 0.05). Markers of onward signalling (Cortisol and TNF-alpha) and tissue repair (PDGF-AA and VEGF) showed a trend towards an elevation at similar timepoints (notably at post-op Day 6) but were not significantly different from baseline levels. There were no observed correlations between inflammatory signal and reported pain, treatment allocation within the trial, burden of implanted prosthetic material, or hernia recurrence.

Discussion

This study demonstrates the novel finding of a pro-inflammatory signal at post-operative Day 30 following the IPOM plus repair.

OC-088 CAN PROCOLLAGEN I AND PROCOLLAGEN III SERVE AS PREDICTIVE BIOMARKERS FOR INCISIONAL HERNIA RECURRENCE?

Background

The aim of this study was to determine the temporal evolution of extracellular matrix (ECM) remodelling and collagen biomarkers and their influence on incisional hernia recurrence after the IPOM plus repair.

Methods

A sub-cohort of patients (n=25) undergoing laparoscopic incisional hernia repair within the TACKoMesh randomised controlled trial were bled at serial timepoints up to 1-year following surgery. Serum/plasma concentration of biomarkers (Procollagen I, Procollagen III, Fibronectin, TGF-beta, MMP-2, MMP-9, TIMP-1, and TIMP-2) were quantified using ELISA and Luminex multiplex techniques. Data were described and compared between groups that developed and remained free from recurrence using R statistical software.

Results

Procollagen I was reduced relative to baseline on post-op Day 1 but increased at Days 6 and 30 (p<0.05). Procollagen III showed an elevation at Day 30. Lower levels of Procollagen I were detected at Day 0, Day 1 and Day 6 (p<0.05) and higher levels of Procollagen III at Day 0, Day 1, Day 6 and Day 30 (p<0.05) in patients with a recurrence.

Fibronectin was reduced at Day 1 and 6 (p<0.05) whilst TGF-β was increased at Day 30 (p<0.05). MMP-2 and its inhibitor TIMP-2 were reduced at post-operative Day 1 (p<0.05). MMP-9 was persistently higher than baseline (p<0.05) at all timepoints. TIMP-1 was elevated at post-op Days 6 and 30. No differences were found in the circulating concentrations of these biomarkers to predict a recurrence.

Conclusion

In patients that developed incisional hernia recurrence, low levels of Procollagen I and high levels of Procollagen III were detected.

OC-086 COMPARISON OF MESH-FIXATION TECHNIQUES IN LAPAROSCOPIC REPAIR OF INCISIONAL HERNIA, RELIATACK™ V PROTACK™ (TACKOMESH) NCT 03434301

Background

A study examining post-op pain, comparing permanent versus absorbable tack fixation devices, Protack™ versus Reliatack™, in IPOM plus repair.

Methods

TACKoMesh is a single-centre double-blind RCT conducted from 2017–2020 with 1-year follow up. Patients were randomised to either Protack™ (titanium tacks) or Reliatack™ (an articulating-arm with dissolvable tacks). Primary outcome was reported pain on activity at Day30. Secondary outcomes include recurrence and quality of life measures (SF-36 & Carolina Comfort Score).

Results

67 patients randomised: 36 with Protack™, 27 with Reliatack™, with 4 conversions. No significant difference in reported pain ‘on activity’ (post-operative Day 1, 6, 30 and 365). There was significantly reduced pain ‘at rest’ on Day1 with Reliatack™ (Protack™ 6 [4 to 9] vs Reliatack™ 4 [3 to 5], p = 0.020) and reduced pain at all other points with Reliatack™.

Operation (p = 0.001) & mesh-fixation (p = 0.001) times were longer, with more knots (p = 0.001) & tacks (p = 0.001) used with Reliatack™.

Entire cohort hernia recurrence, seroma formation, SSI & Clavien-Dindo Grade III-V complication were 8/63 (12.7%), 33/63 (52.4%), 7/63 (11.1%), and 12/63 (19.1%) respectively. There were no significant differences in these outcomes between the treatment groups. CCS showed improvement from post-op Day30 to 365. SF36 showed a reduction in baseline scores at post-op Day30.

Conclusion

There is no difference in reported pain ‘on activity’ following elective IPOM plus hernia repair when choosing either Protack™ or Reliatack™. There is a trend towards improved post-op pain ‘at rest’ with Reliatack™.

Accuracy of echocardiographic doppler measures of pulmonary hypertension compared with right heart catheterisation in a real world population referred to a specialist centre

Introduction

Right heart catheterisation (RHC) is the gold standard investigation for the diagnosis of pulmonary hypertension (PH). Transthoracic echocardiography (TTE) allows non-invasive screening for PH. This retrospective audit sought to compare the accuracy of non-invasive Doppler estimates of pulmonary artery pressure and pulmonary vascular resistance (PVR) compared to RHC in a real world cohort referred to a shared care PH centre.

Method

Between 2010 and 2019, a total of 310 patients referred for initial assessment of PH underwent TTE followed by RHC (mean interval 31±30 days). Bland-Altman analysis was used to retrospectively investigate the accuracy of Doppler estimates of Pulmonary Artery Systolic Pressure (PASP), mean Pulmonary Artery Pressure (mPAP), Right Atrial Pressure (RAP) and PVR compared to RHC. TTE mPAP estimates were made using the pulmonary regurgitation velocity at the beginning of diastole (mPAP = 4(PRVBD)2 + RAP). TTE PVR estimates were calculated using the equation 10(TRV / RVOTVTI) + 0.16.

Results

Seventy-six percent of the cohort (n=235) had RHC diagnosed PH (average mPAP 42.8±11.7mmHg). The peak tricuspid regurgitation velocity (TRV) was measurable in 87% (n=269) and was unmeasurable in 8% (n=19) of those with confirmed RHC PH. Ten percent (n=30) had inadequate IVC imaging. TTE estimates of PASP (n=239) had a good correlation to RHC PASP (rs=0.82, 95% CI 0.75–0.84). TTE PASP estimates tended to underestimate RHC PASP (bias −3.7±15.2mmHg) with wide limits of agreement (95% limits of agreement −33.5–26.1mmHg) (figure 1); highlighting the imprecision of Doppler estimates alone. Only 44% of TTE PASP estimates were within 10mmHg of RHC PASP readings. Underestimation occurred more frequently accounting for 66% of inaccurate TTE PASP estimates. TTE RAP estimates (n=292) were weakly correlated to RHC RAP (rs=0.38, 95% CI 0.27–0.48).

TTE estimates of mPAP were only measurable in 81 patients and demonstrated moderate correlation to RHC mPAP (rs=0.58, 95% CI 0.4–0.71). TTE estimates tended to underestimate RHC mPAP (bias of −10±10.9mmHg) with wide limits of agreement (95% limits of agreement −31.3–11.3mmHg) (figure 1) suggesting poor accuracy and precision. Only 51% of TTE estimates were within 10mmHg of RHC mPAP with 93% of inaccuracies due to an underestimation of RHC mPAP. TTE PVR estimates (n=238) correlated well with RHC PVR measures (rs=0.68, 95% CI 0.6–0.74). However, Bland-Altman analysis (figure 2) demonstrated bias of −2.2±3.1WU with wide limits of agreement (95% limits of agreement −8.2–3.8WU), highlighting significant inaccuracy.

Conclusion

Doppler TTE measures to assess PH lack accuracy when compared with the gold standard RHC. Furthermore, the peak TRV was unmeasurable in 8% of those with confirmed RHC diagnosed PH. These findings further support the use of a multi parameter TTE approach for screening of PH.

Funding Acknowledgement

Type of funding sources: None.

Cortical hyperexcitability in migraine and aversion to patterns

BACKGROUND

Patients with migraine are averse to certain visual stimuli, such as flicker and striped patterns that evoke paroxysmal EEG activity in patients with photosensitive epilepsy. Migraineurs demonstrate a hyper-responsiveness to such stimuli, and there is debate as to whether the aversion and hyper-responsiveness are due to a hyperexcitability of the cortex similar to that in patients with photosensitive epilepsy. In these patients grating patterns with certain spatial characteristics can be epileptogenic, depending critically on their movement. If the contours of the grating drift continually, the grating is not epileptogenic, but if the contours are static or if their direction is repeatedly and rapidly reversed so as to vibrate, the grating then becomes highly epileptogenic.

METHODS

We compared aversion to vibrating, drifting and static gratings in migraineurs and controls. The contrast of each grating was gradually increased, but only until the participant felt discomfort, so as to obtain a contrast threshold for aversion with minimal exposure.

RESULTS

Migraineurs had lower thresholds than the control group, indicating greater aversion. For both groups the threshold was higher (aversion was lower) for static than for both types of moving gratings. The drifting gratings were more aversive than the vibrating gratings when both groups were combined.

CONCLUSION

The findings suggest that the aversion shown by migraineurs is not attributable to a cortical hyperexcitability similar to that in photosensitive epilepsy.

Binocular rivalry in migraine

Cortical hyperexcitability in migraine could arise from abnormally weak inhibition or from strengthened intracortical excitatory mechanisms. The present study employed binocular rivalry to differentiate between these possibilities. Rivalry between static oriented grating patterns was examined in migraine with aura (MA), migraine without aura (MoA) and headache-free control participants. A non-significant trend toward elevated mean dominance intervals (monocular percepts, in seconds) was seen in both migraine groups at all contrasts. Second, significant interocular differences in rivalry dominance durations were seen in the MoA group compared with controls; this difference also approached significance in the MA group. Finally, both MA and MoA exhibited significantly greater visual discomfort than the control group in the presence of both static stripes and flickering visual stimuli. The rivalry results provide no support for weakened intracortical inhibition in migraine. Optical or neural precortical differences in the eyes' input strengths paired with enhanced recurrent cortical excitation can explain these findings.