Abnormal microvascular response is localized to the digits in patients with systemic sclerosis

Effects of Clopidogrel, Prasugrel and Ticagrelor on Microvascular Function and Platelet Reactivity in Patients With Acute Coronary Syndrome Undergoing Coronary Artery Stenting. A Randomized, Blinded, Parallel Group Trial

Aims: In this pre-specified analysis of the "endothelium, stent and antiplatelet therapy" study, we investigate the impact of antiplatelet therapies on microvascular function in patients undergoing stenting for an acute coronary syndrome. Methods and Results: Fifty-six patients [age: 63(55-67) years, males, 10 diabetics, 27 non-ST-elevation myocardial infarction] were randomized to receive clopidogrel, ticagrelor or prasugrel in form of oral loading 2 h before stenting followed by oral therapy. Investigators were blinded to the allocation. Laser-Doppler microvascular function and ADP-induced platelet aggregation capacity were measured at baseline, 2 h after oral antiplatelet loading, and 1 day, 1 week and 1 month after stenting during chronic therapy with the same antiplatelet agent. Platelet aggregation decreased in all groups 2 h after oral loading, with a significantly larger effect in the prasugrel group (P = 0.009). Similarly, prasugrel and ticagrelor loading was followed by an increase in microvascular reactive hyperemia (P = 0.007 and P = 0.042 compared to clopidogrel). This effect disappeared one day after coronary intervention, with a significant decrease in the prasugrel group (P = 0.026). Similarly, analysis of microvascular conductance showed a larger increase in the prasugrel group 2 h after loading (P = 0.022 among groups), and a decrease in all groups after stenting. Conclusions: Oral loading with prasugrel (and less consistently ticagrelor) is associated with improved microvascular function and stronger platelet inhibition in acute coronary syndrome patients. The microvascular effect was however lost 1 day after stenting and during subsequent follow-up. Further studies are necessary to clarify the the long-term effects and potential benefits of P2Y12 inhibitors on microvascular damage. ClINICALTRIALS.gov N°: NCT01700322 EUDRACT-N°: 2011-005305-73.

Performance of finger systolic blood pressure measurement to detect digital occlusive arterial disease in systemic sclerosis

OBJECTIVE

Digital ulcers (DUs) related to digital occlusive arterial disease (DOAD) are frequent in patients with systemic sclerosis (SSc). Finger systolic blood pressure (FSBP) and digital-brachial pressure index (DBI) using laser Doppler flowmetry constitute a non-invasive means of detecting DOAD in SSc, although thresholds have yet to be established for defining DOAD. The purpose of this study was to ascertain FSBP and DBI thresholds to detect DOAD in SSc patients. The intra/interday reproducibility of curve reading by 4 vascular physicians in relation to finger pressure measurement was also investigated.

METHODS

SSc patients were followed in this single-center study (Rennes University Hospital, France) between November 2017 and October 2019.Theses patients underwent tests before and after heating at two visits spaced 10 days apart. DOAD was diagnosed on the basis of post-warming skin blood flow of ≤ 206 arbitrary units measured by LDF, contingent on previous results validated by arteriography as a gold standard. An interday kappa coefficient with a 95% confidence interval was used to assess reproducibility.

RESULTS

16 (10 females; mean age: 63 ± 9 years) SSc patients were included. Mean time interval between visits was 9 ± 5 days. The best FSBP threshold for DOAD diagnosis was 76 mmHg and DBI was 0.74 after warming. FSBP and DBI sensitivity/specificity were 59.1%[49.6%; 68.5%]/92.5% [85.3%; 99.6%] and 73.3%[64.9%; 81.8%]/83.0% [72.9%; 93.1%] respectively. Intra/interday reproducibility ranged from fair to good.

CONCLUSION

The conclusions drawn from this study suggest that FSBP ≤ 76 mmHg and DBI ≤ 0.74 thresholds are potentially reliable indicators of DOAD and demonstrate fair to good intra and interday reproducibility.

Points to consider-Raynaud's phenomenon in systemic sclerosis

RP is an exaggerated vasospastic response to cold or emotion. Randomized, double-blind, placebo-controlled trials with either parallel group or cross-over trials should be mainly considered. Cross-over design, which is good for early phase trials of immediate or very short-term outcomes, is important in a condition as heterogeneous as RP: a wash-out period between treatment arms should always be included to minimize the possibility of a period (carry-over) effect. Duration of RP trials is usually constrained by the need to complete these over a single season, usually winter when the weather is colder. For cross-over trials, each treatment arm tends to be 4 weeks or less. Frequency and duration of attacks, and the Raynaud's Condition Score are widely used outcome measures. There is increasing interest in physiological laboratory endpoints, for example laser Doppler imaging at least for early phase trials.

Correlations between skin blood perfusion values and nailfold capillaroscopy scores in systemic sclerosis patients

OBJECTIVES

To correlate blood perfusion (BP) values assessed by laser speckle contrast analysis (LASCA) in selected skin areas of hands and face with nailfold capillary damage scores in systemic sclerosis (SSc) patients.

METHODS

Seventy SSc patients (mean SSc duration 6 ± 5 years) and 70 volunteer healthy subjects were enrolled after informed consent. LASCA was performed at different areas of the face (forehead, tip of nose, zygomas and perioral region) and at dorsal and volar regions of hands. Microvascular damage was assessed and scored by nailfold videocapillaroscopy (NVC) and the microangiopathy evolution score (MES) was calculated.

RESULTS

SSc patients showed a significantly lower BP than healthy subjects at fingertips, periungual areas and palm of hands (p<0.0001), but not at the level of face and dorsum of hands. A gradual decrease of BP at fingertips, periungual and palm areas, was found in SSc patients with progressive severity of NVC patterns of microangiopathy ("early", "active", or "late") (p<0.01). A negative correlation was observed between MES and BP values, as well as between loss of capillaries and BP, at the same areas (p<0.001 and p<0.01, respectively). Patients with diffuse cutaneous SSc (dcSSc) showed lower BP than those with limited cutaneous SSc (p<0.04).

CONCLUSIONS

LASCA detects a significant reduction of BP only in those areas usually affected by Raynaud's phenomenon (fingertips, periungual and palm areas), especially in dcSSc patients, and BP values significantly correlate with the nailfold capillaroscopy scores of microangiopathy.

Evaluation of the effect of ambrisentan on digital microvascular flow in patients with systemic sclerosis using laser Doppler perfusion imaging: a 12-week randomized double-blind placebo controlled trial

INTRODUCTION

In patients with systemic sclerosis (SSc), digital ischemia results from an occlusive microvasculopathy that may not respond adequately to conventional vasodilators. Endothelin receptor antagonists can potentially modify the fibroproliferative vascular remodeling in SSc, and hence their use may be justified in the management of digital ischemia. The objective of this clinical trial was to evaluate the effect of ambrisentan, a selective endothelin type A receptor antagonist, on microvascular blood flow in patients with limited systemic sclerosis (SSc) using laser Doppler perfusion imaging (LDPI).

METHODS

In this randomized, double-blind, placebo controlled study we enrolled 20 patients with limited SSc. Fifteen patients received ambrisentan 5 mg daily for one month and then 10 mg daily for two months, and five received a placebo. There were three visits: weeks 0 (baseline), one and 12. Three patient-oriented questionnaires were completed at each visit: Scleroderma-Health Assessment Questionnaire (S-HAQ), Raynaud Condition Score (RCS), and Pain-Visual Analog Scale (P-VAS). At each visit, LDPI was used to obtain three blood flow readings involving regions of interest in second to fifth fingers of the non-dominant hand at room temperature (25°C) and after cooling (10°C) for two minutes.

RESULTS

There were 16 females (80%); mean age was 50 years. None of the differences in blood flow (as measured by LDPI) were significant both at baseline and after cooling. However, patients in the ambrisentan group showed significant improvement in the patient-oriented outcomes: RCS (P=0.001) and S-HAQ score (P=0.005).

CONCLUSIONS

This pilot study did not show evidence of significant increase in digital blood flow over time; however, there was an improvement in RCS and S-HAQ score. We conclude that continuous use of ambrisentan for three months does not seem to significantly improve digital blood flow in SSc patients.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01072669. Registered 19 February 2010.

Evaluation of the microcirculation in a rabbit hemorrhagic shock model using laser Doppler imaging

The aim of this study is to evaluate the feasibility of Laser Doppler imaging (LDI) for noninvasive and dynamic assessment of hemorrhagic shock in a rabbit model. A rabbit model of hemorrhagic shock was generated and LDI of the microcirculation in the rabbit ears was performed before and at 0, 30, 60, and 90 min after hemorrhage. The CCD (Charge Coupled Device) image of the ears, the mean arterial pressure (MAP) and the heart rate (HR) were monitored. The mean LDI flux was calculated. The HR of rabbits was significantly (p < 0.05) elevated and the MAP was decreased after hemorrhage, compared to the pre-hemorrhage level. Within the initial 30 min after hemorrhage, the perfusion flux lineally dropped down. In contrast, the MAP values did not differ significantly between the time points of 0 and 30 after hemorrhage (p > 0.05). Both the flux numbers and the red-to-blue color changes on LDI imaging showed the reduction of the microcirculation. LDI imaging is a noninvasive and non-contact approach to evaluate the microcirculation and may offer benefits in the diagnosis and treatment of hemorrhage shock. Further studies are needed to confirm its effectiveness in clinical practice.

Laser speckle contrast analysis: a new method to evaluate peripheral blood perfusion in systemic sclerosis patients

OBJECTIVE

The aim of this pilot study was to assess peripheral blood perfusion (PBP) by a new technique, the laser speckle contrast analysis (LASCA), in systemic sclerosis (SSc) patients showing different patterns of nailfold microangiopathy. Correlations between LASCA and single laser Doppler flowmetry (LDF) analysis were also checked.

METHODS

Sixty-one SSc patients and 61 healthy subjects were enrolled. PBP was evaluated using LASCA and LDF. Scleroderma patterns and microangiopathy evolution score (MES) were assessed by nailfold videocapillaroscopy (NVC).

RESULTS

As detected by LASCA and LDF, PBP was lower in SSc patients than in healthy subjects (p<0.0001), showing SSc patients with the 'Early', 'Active' or 'Late' NVC pattern a progressively lower PBP (p=0.04 and p=0.002, respectively). There was a negative correlation between PBP and MES values (p=0.006 and p=0.002 for LASCA and LDF, respectively). A positive correlation was detected between LASCA and LDF values, in all subjects (p<0.0001). However, LASCA evaluates larger skin areas, is significantly less time consuming, is more accepted by patients and shows lower intra-operator variability than LDF.

CONCLUSIONS

LASCA detected lower PBP in SSc patients than in healthy subjects, and for the first time, LASCA perfusion values were found correlated with progression of NVC patterns of microangiopathy.

Laser Doppler perfusion imaging in systemic sclerosis impaired response to cold stimulation involves digits and hand dorsum

OBJECTIVES

To assess by Laser Doppler perfusion imaging (LDPI) skin blood perfusion of hands in patients with SSc and primary RP (PRP) at baseline and after cold stimulation (CS). In SSc patients, the associations between skin perfusion and nailfold video capillaroscopy (NVC) patterns were also evaluated.

METHODS

Forty patients with SSc, 38 patients with PRP and 32 healthy controls were recruited. Skin blood flow of the hands was detected by Lisca Laser Doppler Perfusion Imager at baseline and after CS. Further laser Doppler scanning was performed for each hand at 0 (T(1)), 3 (T(2)), 7 (T(3)) and 15 min (T(4)).

RESULTS

Baseline mean perfusion is significantly (P < 0.000 l) lower in SSc patients than in healthy controls. In SSc patients, mean perfusion is reduced after CS (P < 0.0001) and skin flow recovery (significant difference between T(0) and T(4), P < 0.0001) is incomplete. In SSc patients with low vascular damage (early and active capillaroscopic groups), the abnormal microvascular response to CS involves only the digits, while the perfusion of hands dorsum is normal. With the progression of vascular damage (late capillaroscopic groups), the abnormal microvascular response to CS also appears in the hand dorsum skin. In PRP patients, baseline hand perfusion is very low and the skin flow recovery after CS is absent (P < 0.05).

CONCLUSION

In early SSc, the thermoregulation of finger skin is impaired, but only in advanced stages of microangiopathy does the skin of the hand dorsum show a vasomotor control failure.

Registry evaluation of digital ulcers in systemic sclerosis

Digital ulcers are a very frequent complication of systemic sclerosis affecting about half of the SSc patients, and about 75% of the affected patients have their first DU episode within 5 years from their first non-Raynaud symptom. The lack of adequate classification criteria as well as the lack of knowledge of the development of DU have contributed to the opening of specific registries to better understand the natural history of these lesions. For these reason, specific disease registries play a fundamental role in this field of research. Thanks to the systematic collection of data and their subsequent analysis and comparison between different cohorts, it is possible to improve understanding of the underlying trigger mechanisms of DU development and to determine temporal trends. In the future, the development of recommendations for the management of DU remains of pivotal importance to prevent DU development and obtain rapid healing as well as reduction of pain and disability.

Peripheral blood perfusion correlates with microvascular abnormalities in systemic sclerosis: a laser-Doppler and nailfold videocapillaroscopy study

OBJECTIVE

To investigate possible correlations between fingertip blood perfusion (FBP) status, assessed by laser Doppler flowmetry (LDF), and morphological microvascular abnormalities, detected by nailfold videocapillaroscopy (NVC), in patients with systemic sclerosis (SSc). The effects on FBP of intravenous (IV) treatment with the prostacyclin analog iloprost were also investigated.

METHODS

Thirty-four consecutive patients with SSc and 16 healthy subjects were evaluated. LDF was performed by analyzing blood perfusion at the fingertips in both hands. Patients with SSc were distributed into the appropriate NVC pattern of microangiopathy (early, active, and late). Iloprost was administered to inpatients with SSc by 24-hour IV infusion for 7 consecutive days (4 microg/h).

RESULTS

FBP was significantly lower in patients with SSc (p < 0.05) compared to controls. Heating of the LDF probe at 36 degrees C induced a significant increase of FBP in all subjects (p < 0.001), but the slope of variation was significantly lower in patients with SSc compared to controls (p < 0.05). Patients with SSc showing the late NVC pattern of microangiopathy had significantly lower FBP than patients with the active and early NVC patterns (p < 0.05). A negative correlation was observed between FBP and NVC rating of the microvascular damage (p < 0.05). After iloprost treatment, a significant increase of FBP was observed in patients with SSc (p < 0.05).

CONCLUSION

Patients with SSc show a decreased FBP partially reversible by local skin heating. The FBP correlated negatively with the extent of nailfold microvascular damage, and IV iloprost treatment increased the FBP.

Reproducibility of a local cooling test to assess microvascular function in human skin

OBJECTIVE

In the present study we aimed to assess the reproducibility of skin microvascular reactivity while fast cooling locally with a custom-designed laser-Doppler flowmetry (LDF) probe.

METHODS

Twenty-two healthy volunteers underwent local 15 degrees C cooling on the forearm during 5 (protocol 1, n=12) or 30 min (protocol 2, n=10). Skin blood flow was concomitantly assessed using LDF. Measurements were repeated after 30 min (protocol 1) or 7 days (protocols 1 and 2). Data were expressed as cutaneous vascular conductance (CVC) and percentage of baseline (%BL). Within subject coefficients of variation (CV) and intra-class correlation coefficients (ICC) were calculated.

RESULTS

Immediate reproducibility of the 5-min cooling was very good, either expressed as CVC or %BL (CV were 8% and 18%; ICC were 0.85 and 0.78, respectively). However, the 30-min cooling was the most reproducible at 1 week, either as CVC or %BL (CV were 26% and 23%; ICC were 0.86 and 0.75, respectively). Local cooling was well tolerated by all volunteers.

CONCLUSIONS

We propose in the present work a reproducible 30-min LDF cooling test. Such a tool could be of great interest to assess microvascular reactivity to local cooling in diseases such as Raynaud's syndrome, and to further evaluate drugs for such diseases.

Noninvasive imaging techniques in the assessment of scleroderma spectrum disorders

OBJECTIVE

Systemic sclerosis (SSc) affects both microvascular structure and function. Laser Doppler imaging (LDI) and thermal imaging can be used to measure cutaneous blood vessel function. Nailfold capillaroscopy (NC) measures capillary morphology. The aim of this study was to investigate the relationship between capillary morphology and blood flow, and to determine which combination of techniques allows the best discrimination between patients with SSc, primary Raynaud's phenomenon (RP), and healthy controls.

METHODS

NC was performed in 16 patients with SSc, 14 patients with primary RP, and 16 healthy controls. In addition, participants underwent cold stimulus with cold water. Hands were imaged to monitor rewarming and reperfusion. Nailfold morphologic features were measured and baseline images and rewarming curves were analyzed.

RESULTS

Significant differences were found between groups (analysis of variance) for capillary morphologic features and rewarming curve characteristics. A correlation (P < 0.001) was found between LDI and thermal imaging at baseline (0.667) and maximum (0.729) blood flow and skin temperature, and for the areas under the rewarming curves (0.684). Receiver operating characteristic curves indicated that NC, thermal imaging, and LDI allowed 89%, 74%, and 72%, respectively, of SSc patient data to be correctly classified versus primary RP patients and controls.

CONCLUSION

NC, LDI, and thermal imaging each independently provide good discrimination between patients with SSc and those with primary RP and healthy controls (NC being the most suitable technique for classifying patient groups). However, a combination of all 3 techniques improves classification. LDI and thermal imaging give equivalent information on dynamic changes in the cutaneous microcirculation; however, these only weakly correspond to capillary morphology.

Hand vascular involvement assessed by magnetic resonance angiography in systemic sclerosis

OBJECTIVE

Impairment of the microcirculation is a cardinal feature of systemic sclerosis (SSc). Magnetic resonance angiography (MRA) has improved the assessment of vascular lesions of the hand. The aim of this study was to evaluate vascular abnormalities in the hands of patients with SSc, using MRA.

METHODS

Thirty-eight patients with SSc were compared with 7 healthy subjects and 7 patients with rheumatoid arthritis. Among patients with SSc, the mean +/- SD age was 52 +/- 14 years, the mean +/- SD Health Assessment Questionnaire (HAQ) score was 0.9 +/- 0.8, and the mean +/- SD systolic pulmonary artery pressure (PAP) was 32.2 +/- 8.4 mm Hg. Ten patients had a history of digital ulcers. The MRA protocol consisted of 4 successive acquisitions, each lasting 52 seconds, of 3-dimensional coronal cross-sectional images after gadolinium injection. The primary criteria were distality and quality of arterial opacification, avascular areas, and venous return.

RESULTS

Thirty-five of the patients with SSc (92%) had at least 1 true digital artery that did not reach the first phalanx at the initial arterial analysis, and 23 patients (61%) had > or =4 damaged arteries. Twenty-eight patients (74%) had thin arteries, and 20 patients (53%) had >1 avascular area. Nearly all patients (35 of 38 [92%]) had abnormal venous return, and a lack of visible venous return was observed in 16 patients (42%). Results for all of the control subjects were considered normal. Digital ulcers were more frequently observed in patients with SSc who had > or =4 damaged proper digital arteries compared with other patients (P = 0.003), the HAQ score was associated with thin-caliber arteries (P = 0.04), and systolic PAP was associated with tissue enhancement secondary to ischemia (P = 0.04).

CONCLUSION

These results show the substantial vascular involvement in SSc. Lesions were diffuse and involved both arterial and venous vessels of small caliber as well as the microcirculation.